Precalculus Examples

Identify the Zeros and Their Multiplicities 9x^5-21x^4+10x^3+6x^2-3x-1
Step 1
Set equal to .
Step 2
Solve for .
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Step 2.1
Factor the left side of the equation.
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Step 2.1.1
Regroup terms.
Step 2.1.2
Factor out of .
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Step 2.1.2.1
Factor out of .
Step 2.1.2.2
Rewrite as .
Step 2.1.2.3
Factor out of .
Step 2.1.3
Factor out of .
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Step 2.1.3.1
Factor out of .
Step 2.1.3.2
Factor out of .
Step 2.1.3.3
Factor out of .
Step 2.1.3.4
Factor out of .
Step 2.1.3.5
Factor out of .
Step 2.1.3.6
Factor out of .
Step 2.1.3.7
Factor out of .
Step 2.1.4
Factor.
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Step 2.1.4.1
Factor using the rational roots test.
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Step 2.1.4.1.1
If a polynomial function has integer coefficients, then every rational zero will have the form where is a factor of the constant and is a factor of the leading coefficient.
Step 2.1.4.1.2
Find every combination of . These are the possible roots of the polynomial function.
Step 2.1.4.1.3
Substitute and simplify the expression. In this case, the expression is equal to so is a root of the polynomial.
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Step 2.1.4.1.3.1
Substitute into the polynomial.
Step 2.1.4.1.3.2
Raise to the power of .
Step 2.1.4.1.3.3
Multiply by .
Step 2.1.4.1.3.4
Raise to the power of .
Step 2.1.4.1.3.5
Multiply by .
Step 2.1.4.1.3.6
Subtract from .
Step 2.1.4.1.3.7
Multiply by .
Step 2.1.4.1.3.8
Subtract from .
Step 2.1.4.1.3.9
Add and .
Step 2.1.4.1.4
Since is a known root, divide the polynomial by to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
Step 2.1.4.1.5
Divide by .
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Step 2.1.4.1.5.1
Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of .
+-++
Step 2.1.4.1.5.2
Divide the highest order term in the dividend by the highest order term in divisor .
+-++
Step 2.1.4.1.5.3
Multiply the new quotient term by the divisor.
+-++
++
Step 2.1.4.1.5.4
The expression needs to be subtracted from the dividend, so change all the signs in
+-++
--
Step 2.1.4.1.5.5
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+-++
--
-
Step 2.1.4.1.5.6
Pull the next terms from the original dividend down into the current dividend.
+-++
--
-+
Step 2.1.4.1.5.7
Divide the highest order term in the dividend by the highest order term in divisor .
-
+-++
--
-+
Step 2.1.4.1.5.8
Multiply the new quotient term by the divisor.
-
+-++
--
-+
--
Step 2.1.4.1.5.9
The expression needs to be subtracted from the dividend, so change all the signs in
-
+-++
--
-+
++
Step 2.1.4.1.5.10
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-
+-++
--
-+
++
+
Step 2.1.4.1.5.11
Pull the next terms from the original dividend down into the current dividend.
-
+-++
--
-+
++
++
Step 2.1.4.1.5.12
Divide the highest order term in the dividend by the highest order term in divisor .
-+
+-++
--
-+
++
++
Step 2.1.4.1.5.13
Multiply the new quotient term by the divisor.
-+
+-++
--
-+
++
++
++
Step 2.1.4.1.5.14
The expression needs to be subtracted from the dividend, so change all the signs in
-+
+-++
--
-+
++
++
--
Step 2.1.4.1.5.15
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-+
+-++
--
-+
++
++
--
Step 2.1.4.1.5.16
Since the remander is , the final answer is the quotient.
Step 2.1.4.1.6
Write as a set of factors.
Step 2.1.4.2
Remove unnecessary parentheses.
Step 2.1.5
Factor out of .
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Step 2.1.5.1
Factor out of .
Step 2.1.5.2
Factor out of .
Step 2.1.5.3
Factor out of .
Step 2.1.6
Apply the distributive property.
Step 2.1.7
Simplify.
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Step 2.1.7.1
Rewrite using the commutative property of multiplication.
Step 2.1.7.2
Rewrite using the commutative property of multiplication.
Step 2.1.7.3
Move to the left of .
Step 2.1.8
Simplify each term.
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Step 2.1.8.1
Multiply by by adding the exponents.
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Step 2.1.8.1.1
Move .
Step 2.1.8.1.2
Use the power rule to combine exponents.
Step 2.1.8.1.3
Add and .
Step 2.1.8.2
Multiply by by adding the exponents.
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Step 2.1.8.2.1
Move .
Step 2.1.8.2.2
Multiply by .
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Step 2.1.8.2.2.1
Raise to the power of .
Step 2.1.8.2.2.2
Use the power rule to combine exponents.
Step 2.1.8.2.3
Add and .
Step 2.1.9
Reorder terms.
Step 2.1.10
Factor.
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Step 2.1.10.1
Rewrite in a factored form.
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Step 2.1.10.1.1
Factor using the rational roots test.
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Step 2.1.10.1.1.1
If a polynomial function has integer coefficients, then every rational zero will have the form where is a factor of the constant and is a factor of the leading coefficient.
Step 2.1.10.1.1.2
Find every combination of . These are the possible roots of the polynomial function.
Step 2.1.10.1.1.3
Substitute and simplify the expression. In this case, the expression is equal to so is a root of the polynomial.
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Step 2.1.10.1.1.3.1
Substitute into the polynomial.
Step 2.1.10.1.1.3.2
Raise to the power of .
Step 2.1.10.1.1.3.3
Multiply by .
Step 2.1.10.1.1.3.4
Raise to the power of .
Step 2.1.10.1.1.3.5
Multiply by .
Step 2.1.10.1.1.3.6
Add and .
Step 2.1.10.1.1.3.7
Raise to the power of .
Step 2.1.10.1.1.3.8
Multiply by .
Step 2.1.10.1.1.3.9
Add and .
Step 2.1.10.1.1.3.10
Subtract from .
Step 2.1.10.1.1.4
Since is a known root, divide the polynomial by to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
Step 2.1.10.1.1.5
Divide by .
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Step 2.1.10.1.1.5.1
Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of .
+-++-
Step 2.1.10.1.1.5.2
Divide the highest order term in the dividend by the highest order term in divisor .
+-++-
Step 2.1.10.1.1.5.3
Multiply the new quotient term by the divisor.
+-++-
++
Step 2.1.10.1.1.5.4
The expression needs to be subtracted from the dividend, so change all the signs in
+-++-
--
Step 2.1.10.1.1.5.5
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
+-++-
--
-
Step 2.1.10.1.1.5.6
Pull the next terms from the original dividend down into the current dividend.
+-++-
--
-+
Step 2.1.10.1.1.5.7
Divide the highest order term in the dividend by the highest order term in divisor .
-
+-++-
--
-+
Step 2.1.10.1.1.5.8
Multiply the new quotient term by the divisor.
-
+-++-
--
-+
--
Step 2.1.10.1.1.5.9
The expression needs to be subtracted from the dividend, so change all the signs in
-
+-++-
--
-+
++
Step 2.1.10.1.1.5.10
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-
+-++-
--
-+
++
+
Step 2.1.10.1.1.5.11
Pull the next terms from the original dividend down into the current dividend.
-
+-++-
--
-+
++
++
Step 2.1.10.1.1.5.12
Divide the highest order term in the dividend by the highest order term in divisor .
-+
+-++-
--
-+
++
++
Step 2.1.10.1.1.5.13
Multiply the new quotient term by the divisor.
-+
+-++-
--
-+
++
++
++
Step 2.1.10.1.1.5.14
The expression needs to be subtracted from the dividend, so change all the signs in
-+
+-++-
--
-+
++
++
--
Step 2.1.10.1.1.5.15
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-+
+-++-
--
-+
++
++
--
-
Step 2.1.10.1.1.5.16
Pull the next terms from the original dividend down into the current dividend.
-+
+-++-
--
-+
++
++
--
--
Step 2.1.10.1.1.5.17
Divide the highest order term in the dividend by the highest order term in divisor .
-+-
+-++-
--
-+
++
++
--
--
Step 2.1.10.1.1.5.18
Multiply the new quotient term by the divisor.
-+-
+-++-
--
-+
++
++
--
--
--
Step 2.1.10.1.1.5.19
The expression needs to be subtracted from the dividend, so change all the signs in
-+-
+-++-
--
-+
++
++
--
--
++
Step 2.1.10.1.1.5.20
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-+-
+-++-
--
-+
++
++
--
--
++
Step 2.1.10.1.1.5.21
Since the remander is , the final answer is the quotient.
Step 2.1.10.1.1.6
Write as a set of factors.
Step 2.1.10.1.2
Factor using the rational roots test.
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Step 2.1.10.1.2.1
If a polynomial function has integer coefficients, then every rational zero will have the form where is a factor of the constant and is a factor of the leading coefficient.
Step 2.1.10.1.2.2
Find every combination of . These are the possible roots of the polynomial function.
Step 2.1.10.1.2.3
Substitute and simplify the expression. In this case, the expression is equal to so is a root of the polynomial.
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Step 2.1.10.1.2.3.1
Substitute into the polynomial.
Step 2.1.10.1.2.3.2
Raise to the power of .
Step 2.1.10.1.2.3.3
Raise to the power of .
Step 2.1.10.1.2.3.4
Multiply by .
Step 2.1.10.1.2.3.5
Subtract from .
Step 2.1.10.1.2.3.6
Multiply by .
Step 2.1.10.1.2.3.7
Add and .
Step 2.1.10.1.2.3.8
Subtract from .
Step 2.1.10.1.2.4
Since is a known root, divide the polynomial by to find the quotient polynomial. This polynomial can then be used to find the remaining roots.
Step 2.1.10.1.2.5
Divide by .
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Step 2.1.10.1.2.5.1
Set up the polynomials to be divided. If there is not a term for every exponent, insert one with a value of .
--+-
Step 2.1.10.1.2.5.2
Divide the highest order term in the dividend by the highest order term in divisor .
--+-
Step 2.1.10.1.2.5.3
Multiply the new quotient term by the divisor.
--+-
+-
Step 2.1.10.1.2.5.4
The expression needs to be subtracted from the dividend, so change all the signs in
--+-
-+
Step 2.1.10.1.2.5.5
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
--+-
-+
-
Step 2.1.10.1.2.5.6
Pull the next terms from the original dividend down into the current dividend.
--+-
-+
-+
Step 2.1.10.1.2.5.7
Divide the highest order term in the dividend by the highest order term in divisor .
-
--+-
-+
-+
Step 2.1.10.1.2.5.8
Multiply the new quotient term by the divisor.
-
--+-
-+
-+
-+
Step 2.1.10.1.2.5.9
The expression needs to be subtracted from the dividend, so change all the signs in
-
--+-
-+
-+
+-
Step 2.1.10.1.2.5.10
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-
--+-
-+
-+
+-
+
Step 2.1.10.1.2.5.11
Pull the next terms from the original dividend down into the current dividend.
-
--+-
-+
-+
+-
+-
Step 2.1.10.1.2.5.12
Divide the highest order term in the dividend by the highest order term in divisor .
-+
--+-
-+
-+
+-
+-
Step 2.1.10.1.2.5.13
Multiply the new quotient term by the divisor.
-+
--+-
-+
-+
+-
+-
+-
Step 2.1.10.1.2.5.14
The expression needs to be subtracted from the dividend, so change all the signs in
-+
--+-
-+
-+
+-
+-
-+
Step 2.1.10.1.2.5.15
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-+
--+-
-+
-+
+-
+-
-+
Step 2.1.10.1.2.5.16
Since the remander is , the final answer is the quotient.
Step 2.1.10.1.2.6
Write as a set of factors.
Step 2.1.10.1.3
Factor using the perfect square rule.
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Step 2.1.10.1.3.1
Rewrite as .
Step 2.1.10.1.3.2
Check that the middle term is two times the product of the numbers being squared in the first term and third term.
Step 2.1.10.1.3.3
Rewrite the polynomial.
Step 2.1.10.1.3.4
Factor using the perfect square trinomial rule , where and .
Step 2.1.10.1.4
Combine like factors.
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Step 2.1.10.1.4.1
Raise to the power of .
Step 2.1.10.1.4.2
Use the power rule to combine exponents.
Step 2.1.10.1.4.3
Add and .
Step 2.1.10.2
Remove unnecessary parentheses.
Step 2.1.11
Combine exponents.
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Step 2.1.11.1
Raise to the power of .
Step 2.1.11.2
Raise to the power of .
Step 2.1.11.3
Use the power rule to combine exponents.
Step 2.1.11.4
Add and .
Step 2.2
If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .
Step 2.3
Set equal to and solve for .
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Step 2.3.1
Set equal to .
Step 2.3.2
Solve for .
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Step 2.3.2.1
Set the equal to .
Step 2.3.2.2
Solve for .
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Step 2.3.2.2.1
Subtract from both sides of the equation.
Step 2.3.2.2.2
Divide each term in by and simplify.
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Step 2.3.2.2.2.1
Divide each term in by .
Step 2.3.2.2.2.2
Simplify the left side.
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Step 2.3.2.2.2.2.1
Cancel the common factor of .
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Step 2.3.2.2.2.2.1.1
Cancel the common factor.
Step 2.3.2.2.2.2.1.2
Divide by .
Step 2.3.2.2.2.3
Simplify the right side.
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Step 2.3.2.2.2.3.1
Move the negative in front of the fraction.
Step 2.4
Set equal to and solve for .
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Step 2.4.1
Set equal to .
Step 2.4.2
Solve for .
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Step 2.4.2.1
Set the equal to .
Step 2.4.2.2
Add to both sides of the equation.
Step 2.5
The final solution is all the values that make true. The multiplicity of a root is the number of times the root appears.
(Multiplicity of )
(Multiplicity of )
(Multiplicity of )
(Multiplicity of )
Step 3