Precalculus Examples

Solve by Substitution xy=7 , 7x^2+y^2=56
,
Step 1
Divide each term in by and simplify.
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Step 1.1
Divide each term in by .
Step 1.2
Simplify the left side.
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Step 1.2.1
Cancel the common factor of .
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Step 1.2.1.1
Cancel the common factor.
Step 1.2.1.2
Divide by .
Step 2
Replace all occurrences of with in each equation.
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Step 2.1
Replace all occurrences of in with .
Step 2.2
Simplify the left side.
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Step 2.2.1
Simplify each term.
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Step 2.2.1.1
Apply the product rule to .
Step 2.2.1.2
Raise to the power of .
Step 2.2.1.3
Multiply .
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Step 2.2.1.3.1
Combine and .
Step 2.2.1.3.2
Multiply by .
Step 3
Solve for in .
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Step 3.1
Find the LCD of the terms in the equation.
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Step 3.1.1
Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.
Step 3.1.2
The LCM of one and any expression is the expression.
Step 3.2
Multiply each term in by to eliminate the fractions.
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Step 3.2.1
Multiply each term in by .
Step 3.2.2
Simplify the left side.
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Step 3.2.2.1
Simplify each term.
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Step 3.2.2.1.1
Cancel the common factor of .
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Step 3.2.2.1.1.1
Cancel the common factor.
Step 3.2.2.1.1.2
Rewrite the expression.
Step 3.2.2.1.2
Multiply by by adding the exponents.
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Step 3.2.2.1.2.1
Use the power rule to combine exponents.
Step 3.2.2.1.2.2
Add and .
Step 3.3
Solve the equation.
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Step 3.3.1
Subtract from both sides of the equation.
Step 3.3.2
Substitute into the equation. This will make the quadratic formula easy to use.
Step 3.3.3
Factor using the AC method.
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Step 3.3.3.1
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 3.3.3.2
Write the factored form using these integers.
Step 3.3.4
If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .
Step 3.3.5
Set equal to and solve for .
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Step 3.3.5.1
Set equal to .
Step 3.3.5.2
Add to both sides of the equation.
Step 3.3.6
Set equal to and solve for .
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Step 3.3.6.1
Set equal to .
Step 3.3.6.2
Add to both sides of the equation.
Step 3.3.7
The final solution is all the values that make true.
Step 3.3.8
Substitute the real value of back into the solved equation.
Step 3.3.9
Solve the first equation for .
Step 3.3.10
Solve the equation for .
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Step 3.3.10.1
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 3.3.10.2
Simplify .
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Step 3.3.10.2.1
Rewrite as .
Step 3.3.10.2.2
Pull terms out from under the radical, assuming positive real numbers.
Step 3.3.10.3
The complete solution is the result of both the positive and negative portions of the solution.
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Step 3.3.10.3.1
First, use the positive value of the to find the first solution.
Step 3.3.10.3.2
Next, use the negative value of the to find the second solution.
Step 3.3.10.3.3
The complete solution is the result of both the positive and negative portions of the solution.
Step 3.3.11
Solve the second equation for .
Step 3.3.12
Solve the equation for .
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Step 3.3.12.1
Remove parentheses.
Step 3.3.12.2
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 3.3.12.3
The complete solution is the result of both the positive and negative portions of the solution.
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Step 3.3.12.3.1
First, use the positive value of the to find the first solution.
Step 3.3.12.3.2
Next, use the negative value of the to find the second solution.
Step 3.3.12.3.3
The complete solution is the result of both the positive and negative portions of the solution.
Step 3.3.13
The solution to is .
Step 4
Replace all occurrences of with in each equation.
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Step 4.1
Replace all occurrences of in with .
Step 4.2
Simplify the right side.
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Step 4.2.1
Divide by .
Step 5
Replace all occurrences of with in each equation.
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Step 5.1
Replace all occurrences of in with .
Step 5.2
Simplify the right side.
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Step 5.2.1
Divide by .
Step 6
Replace all occurrences of with in each equation.
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Step 6.1
Replace all occurrences of in with .
Step 6.2
Simplify the right side.
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Step 6.2.1
Divide by .
Step 7
Replace all occurrences of with in each equation.
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Step 7.1
Replace all occurrences of in with .
Step 7.2
Simplify the right side.
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Step 7.2.1
Divide by .
Step 8
Replace all occurrences of with in each equation.
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Step 8.1
Replace all occurrences of in with .
Step 8.2
Simplify the right side.
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Step 8.2.1
Simplify .
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Step 8.2.1.1
Multiply by .
Step 8.2.1.2
Combine and simplify the denominator.
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Step 8.2.1.2.1
Multiply by .
Step 8.2.1.2.2
Raise to the power of .
Step 8.2.1.2.3
Raise to the power of .
Step 8.2.1.2.4
Use the power rule to combine exponents.
Step 8.2.1.2.5
Add and .
Step 8.2.1.2.6
Rewrite as .
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Step 8.2.1.2.6.1
Use to rewrite as .
Step 8.2.1.2.6.2
Apply the power rule and multiply exponents, .
Step 8.2.1.2.6.3
Combine and .
Step 8.2.1.2.6.4
Cancel the common factor of .
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Step 8.2.1.2.6.4.1
Cancel the common factor.
Step 8.2.1.2.6.4.2
Rewrite the expression.
Step 8.2.1.2.6.5
Evaluate the exponent.
Step 8.2.1.3
Cancel the common factor of .
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Step 8.2.1.3.1
Cancel the common factor.
Step 8.2.1.3.2
Divide by .
Step 9
Replace all occurrences of with in each equation.
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Step 9.1
Replace all occurrences of in with .
Step 9.2
Simplify the right side.
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Step 9.2.1
Divide by .
Step 10
Replace all occurrences of with in each equation.
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Step 10.1
Replace all occurrences of in with .
Step 10.2
Simplify the right side.
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Step 10.2.1
Divide by .
Step 11
Replace all occurrences of with in each equation.
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Step 11.1
Replace all occurrences of in with .
Step 11.2
Simplify the right side.
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Step 11.2.1
Simplify .
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Step 11.2.1.1
Multiply by .
Step 11.2.1.2
Combine and simplify the denominator.
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Step 11.2.1.2.1
Multiply by .
Step 11.2.1.2.2
Raise to the power of .
Step 11.2.1.2.3
Raise to the power of .
Step 11.2.1.2.4
Use the power rule to combine exponents.
Step 11.2.1.2.5
Add and .
Step 11.2.1.2.6
Rewrite as .
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Step 11.2.1.2.6.1
Use to rewrite as .
Step 11.2.1.2.6.2
Apply the power rule and multiply exponents, .
Step 11.2.1.2.6.3
Combine and .
Step 11.2.1.2.6.4
Cancel the common factor of .
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Step 11.2.1.2.6.4.1
Cancel the common factor.
Step 11.2.1.2.6.4.2
Rewrite the expression.
Step 11.2.1.2.6.5
Evaluate the exponent.
Step 11.2.1.3
Cancel the common factor of .
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Step 11.2.1.3.1
Cancel the common factor.
Step 11.2.1.3.2
Divide by .
Step 12
Replace all occurrences of with in each equation.
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Step 12.1
Replace all occurrences of in with .
Step 12.2
Simplify the right side.
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Step 12.2.1
Simplify .
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Step 12.2.1.1
Move the negative in front of the fraction.
Step 12.2.1.2
Multiply by .
Step 12.2.1.3
Combine and simplify the denominator.
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Step 12.2.1.3.1
Multiply by .
Step 12.2.1.3.2
Raise to the power of .
Step 12.2.1.3.3
Raise to the power of .
Step 12.2.1.3.4
Use the power rule to combine exponents.
Step 12.2.1.3.5
Add and .
Step 12.2.1.3.6
Rewrite as .
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Step 12.2.1.3.6.1
Use to rewrite as .
Step 12.2.1.3.6.2
Apply the power rule and multiply exponents, .
Step 12.2.1.3.6.3
Combine and .
Step 12.2.1.3.6.4
Cancel the common factor of .
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Step 12.2.1.3.6.4.1
Cancel the common factor.
Step 12.2.1.3.6.4.2
Rewrite the expression.
Step 12.2.1.3.6.5
Evaluate the exponent.
Step 12.2.1.4
Cancel the common factor of .
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Step 12.2.1.4.1
Cancel the common factor.
Step 12.2.1.4.2
Divide by .
Step 13
The solution to the system is the complete set of ordered pairs that are valid solutions.
Step 14
The result can be shown in multiple forms.
Point Form:
Equation Form:
Step 15