Precalculus Examples

Solve by Substitution 4x^2+9y^2=72 , 4x-3y^2=0
,
Step 1
Solve for in .
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Step 1.1
Add to both sides of the equation.
Step 1.2
Divide each term in by and simplify.
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Step 1.2.1
Divide each term in by .
Step 1.2.2
Simplify the left side.
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Step 1.2.2.1
Cancel the common factor of .
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Step 1.2.2.1.1
Cancel the common factor.
Step 1.2.2.1.2
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
Use the power rule to distribute the exponent.
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Step 2.2.1.1.1
Apply the product rule to .
Step 2.2.1.1.2
Apply the product rule to .
Step 2.2.1.2
Simplify the numerator.
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Step 2.2.1.2.1
Raise to the power of .
Step 2.2.1.2.2
Multiply the exponents in .
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Step 2.2.1.2.2.1
Apply the power rule and multiply exponents, .
Step 2.2.1.2.2.2
Multiply by .
Step 2.2.1.3
Raise to the power of .
Step 2.2.1.4
Cancel the common factor of .
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Step 2.2.1.4.1
Factor out of .
Step 2.2.1.4.2
Cancel the common factor.
Step 2.2.1.4.3
Rewrite the expression.
Step 3
Solve for in .
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Step 3.1
Multiply each term in by to eliminate the fractions.
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Step 3.1.1
Multiply each term in by .
Step 3.1.2
Simplify the left side.
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Step 3.1.2.1
Simplify each term.
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Step 3.1.2.1.1
Cancel the common factor of .
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Step 3.1.2.1.1.1
Cancel the common factor.
Step 3.1.2.1.1.2
Rewrite the expression.
Step 3.1.2.1.2
Multiply by .
Step 3.1.3
Simplify the right side.
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Step 3.1.3.1
Multiply by .
Step 3.2
Subtract from both sides of the equation.
Step 3.3
Factor the left side of the equation.
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Step 3.3.1
Factor out of .
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Step 3.3.1.1
Factor out of .
Step 3.3.1.2
Factor out of .
Step 3.3.1.3
Factor out of .
Step 3.3.1.4
Factor out of .
Step 3.3.1.5
Factor out of .
Step 3.3.2
Rewrite as .
Step 3.3.3
Let . Substitute for all occurrences of .
Step 3.3.4
Factor using the AC method.
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Step 3.3.4.1
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 3.3.4.2
Write the factored form using these integers.
Step 3.3.5
Replace all occurrences of with .
Step 3.3.6
Rewrite as .
Step 3.3.7
Factor.
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Step 3.3.7.1
Since both terms are perfect squares, factor using the difference of squares formula, where and .
Step 3.3.7.2
Remove unnecessary parentheses.
Step 3.4
If any individual factor on the left side of the equation is equal to , the entire expression will be equal to .
Step 3.5
Set equal to and solve for .
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Step 3.5.1
Set equal to .
Step 3.5.2
Subtract from both sides of the equation.
Step 3.6
Set equal to and solve for .
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Step 3.6.1
Set equal to .
Step 3.6.2
Add to both sides of the equation.
Step 3.7
Set equal to and solve for .
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Step 3.7.1
Set equal to .
Step 3.7.2
Solve for .
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Step 3.7.2.1
Subtract from both sides of the equation.
Step 3.7.2.2
Take the specified root of both sides of the equation to eliminate the exponent on the left side.
Step 3.7.2.3
Simplify .
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Step 3.7.2.3.1
Rewrite as .
Step 3.7.2.3.2
Rewrite as .
Step 3.7.2.3.3
Rewrite as .
Step 3.7.2.3.4
Rewrite as .
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Step 3.7.2.3.4.1
Factor out of .
Step 3.7.2.3.4.2
Rewrite as .
Step 3.7.2.3.5
Pull terms out from under the radical.
Step 3.7.2.3.6
Move to the left of .
Step 3.7.2.4
The complete solution is the result of both the positive and negative portions of the solution.
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Step 3.7.2.4.1
First, use the positive value of the to find the first solution.
Step 3.7.2.4.2
Next, use the negative value of the to find the second solution.
Step 3.7.2.4.3
The complete solution is the result of both the positive and negative portions of the solution.
Step 3.8
The final solution is all the values that make true.
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
Simplify .
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Step 4.2.1.1
Raise to the power of .
Step 4.2.1.2
Multiply by .
Step 4.2.1.3
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
Simplify .
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Step 5.2.1.1
Raise to the power of .
Step 5.2.1.2
Multiply by .
Step 5.2.1.3
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
Simplify .
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Step 6.2.1.1
Raise to the power of .
Step 6.2.1.2
Multiply by .
Step 6.2.1.3
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
Simplify .
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Step 7.2.1.1
Raise to the power of .
Step 7.2.1.2
Multiply by .
Step 7.2.1.3
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
Simplify the numerator.
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Step 8.2.1.1.1
Apply the product rule to .
Step 8.2.1.1.2
Apply the product rule to .
Step 8.2.1.1.3
Raise to the power of .
Step 8.2.1.1.4
Rewrite as .
Step 8.2.1.1.5
Multiply by .
Step 8.2.1.1.6
Rewrite as .
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Step 8.2.1.1.6.1
Use to rewrite as .
Step 8.2.1.1.6.2
Apply the power rule and multiply exponents, .
Step 8.2.1.1.6.3
Combine and .
Step 8.2.1.1.6.4
Cancel the common factor of .
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Step 8.2.1.1.6.4.1
Cancel the common factor.
Step 8.2.1.1.6.4.2
Rewrite the expression.
Step 8.2.1.1.6.5
Evaluate the exponent.
Step 8.2.1.1.7
Combine exponents.
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Step 8.2.1.1.7.1
Multiply by .
Step 8.2.1.1.7.2
Multiply by .
Step 8.2.1.2
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
Simplify .
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Step 9.2.1.1
Raise to the power of .
Step 9.2.1.2
Multiply by .
Step 9.2.1.3
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
Simplify .
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Step 10.2.1.1
Raise to the power of .
Step 10.2.1.2
Multiply by .
Step 10.2.1.3
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
Simplify the numerator.
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Step 11.2.1.1.1
Apply the product rule to .
Step 11.2.1.1.2
Apply the product rule to .
Step 11.2.1.1.3
Raise to the power of .
Step 11.2.1.1.4
Rewrite as .
Step 11.2.1.1.5
Multiply by .
Step 11.2.1.1.6
Rewrite as .
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Step 11.2.1.1.6.1
Use to rewrite as .
Step 11.2.1.1.6.2
Apply the power rule and multiply exponents, .
Step 11.2.1.1.6.3
Combine and .
Step 11.2.1.1.6.4
Cancel the common factor of .
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Step 11.2.1.1.6.4.1
Cancel the common factor.
Step 11.2.1.1.6.4.2
Rewrite the expression.
Step 11.2.1.1.6.5
Evaluate the exponent.
Step 11.2.1.1.7
Combine exponents.
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Step 11.2.1.1.7.1
Multiply by .
Step 11.2.1.1.7.2
Multiply by .
Step 11.2.1.2
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
Simplify the numerator.
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Step 12.2.1.1.1
Apply the product rule to .
Step 12.2.1.1.2
Apply the product rule to .
Step 12.2.1.1.3
Raise to the power of .
Step 12.2.1.1.4
Rewrite as .
Step 12.2.1.1.5
Multiply by .
Step 12.2.1.1.6
Rewrite as .
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Step 12.2.1.1.6.1
Use to rewrite as .
Step 12.2.1.1.6.2
Apply the power rule and multiply exponents, .
Step 12.2.1.1.6.3
Combine and .
Step 12.2.1.1.6.4
Cancel the common factor of .
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Step 12.2.1.1.6.4.1
Cancel the common factor.
Step 12.2.1.1.6.4.2
Rewrite the expression.
Step 12.2.1.1.6.5
Evaluate the exponent.
Step 12.2.1.1.7
Combine exponents.
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Step 12.2.1.1.7.1
Multiply by .
Step 12.2.1.1.7.2
Multiply by .
Step 12.2.1.2
Divide by .
Step 13
List all of the solutions.
Step 14