Precalculus Examples

Solve for x x^3-9x^2+20x-12=0
Step 1
Factor the left side of the equation.
Tap for more steps...
Step 1.1
Factor using the rational roots test.
Tap for more steps...
Step 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 1.1.2
Find every combination of . These are the possible roots of the polynomial function.
Step 1.1.3
Substitute and simplify the expression. In this case, the expression is equal to so is a root of the polynomial.
Tap for more steps...
Step 1.1.3.1
Substitute into the polynomial.
Step 1.1.3.2
Raise to the power of .
Step 1.1.3.3
Raise to the power of .
Step 1.1.3.4
Multiply by .
Step 1.1.3.5
Subtract from .
Step 1.1.3.6
Multiply by .
Step 1.1.3.7
Add and .
Step 1.1.3.8
Subtract from .
Step 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 1.1.5
Divide by .
Tap for more steps...
Step 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 1.1.5.2
Divide the highest order term in the dividend by the highest order term in divisor .
--+-
Step 1.1.5.3
Multiply the new quotient term by the divisor.
--+-
+-
Step 1.1.5.4
The expression needs to be subtracted from the dividend, so change all the signs in
--+-
-+
Step 1.1.5.5
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
--+-
-+
-
Step 1.1.5.6
Pull the next terms from the original dividend down into the current dividend.
--+-
-+
-+
Step 1.1.5.7
Divide the highest order term in the dividend by the highest order term in divisor .
-
--+-
-+
-+
Step 1.1.5.8
Multiply the new quotient term by the divisor.
-
--+-
-+
-+
-+
Step 1.1.5.9
The expression needs to be subtracted from the dividend, so change all the signs in
-
--+-
-+
-+
+-
Step 1.1.5.10
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-
--+-
-+
-+
+-
+
Step 1.1.5.11
Pull the next terms from the original dividend down into the current dividend.
-
--+-
-+
-+
+-
+-
Step 1.1.5.12
Divide the highest order term in the dividend by the highest order term in divisor .
-+
--+-
-+
-+
+-
+-
Step 1.1.5.13
Multiply the new quotient term by the divisor.
-+
--+-
-+
-+
+-
+-
+-
Step 1.1.5.14
The expression needs to be subtracted from the dividend, so change all the signs in
-+
--+-
-+
-+
+-
+-
-+
Step 1.1.5.15
After changing the signs, add the last dividend from the multiplied polynomial to find the new dividend.
-+
--+-
-+
-+
+-
+-
-+
Step 1.1.5.16
Since the remander is , the final answer is the quotient.
Step 1.1.6
Write as a set of factors.
Step 1.2
Factor using the AC method.
Tap for more steps...
Step 1.2.1
Factor using the AC method.
Tap for more steps...
Step 1.2.1.1
Consider the form . Find a pair of integers whose product is and whose sum is . In this case, whose product is and whose sum is .
Step 1.2.1.2
Write the factored form using these integers.
Step 1.2.2
Remove unnecessary parentheses.
Step 2
If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .
Step 3
Set equal to and solve for .
Tap for more steps...
Step 3.1
Set equal to .
Step 3.2
Add to both sides of the equation.
Step 4
Set equal to and solve for .
Tap for more steps...
Step 4.1
Set equal to .
Step 4.2
Add to both sides of the equation.
Step 5
Set equal to and solve for .
Tap for more steps...
Step 5.1
Set equal to .
Step 5.2
Add to both sides of the equation.
Step 6
The final solution is all the values that make true.