Precalculus Examples

Find the Inverse f(x)=(x-3)/(x+2)
Step 1
Write as an equation.
Step 2
Interchange the variables.
Step 3
Solve for .
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Step 3.1
Rewrite the equation as .
Step 3.2
Find the LCD of the terms in the equation.
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Step 3.2.1
Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.
Step 3.2.2
Remove parentheses.
Step 3.2.3
The LCM of one and any expression is the expression.
Step 3.3
Multiply each term in by to eliminate the fractions.
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Step 3.3.1
Multiply each term in by .
Step 3.3.2
Simplify the left side.
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Step 3.3.2.1
Cancel the common factor of .
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Step 3.3.2.1.1
Cancel the common factor.
Step 3.3.2.1.2
Rewrite the expression.
Step 3.3.3
Simplify the right side.
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Step 3.3.3.1
Apply the distributive property.
Step 3.3.3.2
Move to the left of .
Step 3.4
Solve the equation.
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Step 3.4.1
Subtract from both sides of the equation.
Step 3.4.2
Add to both sides of the equation.
Step 3.4.3
Factor out of .
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Step 3.4.3.1
Factor out of .
Step 3.4.3.2
Factor out of .
Step 3.4.3.3
Factor out of .
Step 3.4.4
Divide each term in by and simplify.
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Step 3.4.4.1
Divide each term in by .
Step 3.4.4.2
Simplify the left side.
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Step 3.4.4.2.1
Cancel the common factor of .
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Step 3.4.4.2.1.1
Cancel the common factor.
Step 3.4.4.2.1.2
Divide by .
Step 3.4.4.3
Simplify the right side.
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Step 3.4.4.3.1
Combine the numerators over the common denominator.
Step 4
Replace with to show the final answer.
Step 5
Verify if is the inverse of .
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Step 5.1
To verify the inverse, check if and .
Step 5.2
Evaluate .
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Step 5.2.1
Set up the composite result function.
Step 5.2.2
Evaluate by substituting in the value of into .
Step 5.2.3
Multiply the numerator and denominator of the fraction by .
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Step 5.2.3.1
Multiply by .
Step 5.2.3.2
Combine.
Step 5.2.4
Apply the distributive property.
Step 5.2.5
Cancel the common factor of .
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Step 5.2.5.1
Move the leading negative in into the numerator.
Step 5.2.5.2
Cancel the common factor.
Step 5.2.5.3
Rewrite the expression.
Step 5.2.6
Simplify the numerator.
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Step 5.2.6.1
Factor out of .
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Step 5.2.6.1.1
Factor out of .
Step 5.2.6.1.2
Factor out of .
Step 5.2.6.1.3
Factor out of .
Step 5.2.6.2
Combine and .
Step 5.2.6.3
To write as a fraction with a common denominator, multiply by .
Step 5.2.6.4
Combine the numerators over the common denominator.
Step 5.2.6.5
Reorder terms.
Step 5.2.6.6
Rewrite in a factored form.
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Step 5.2.6.6.1
Apply the distributive property.
Step 5.2.6.6.2
Multiply by .
Step 5.2.6.6.3
Apply the distributive property.
Step 5.2.6.6.4
Multiply by .
Step 5.2.6.6.5
Add and .
Step 5.2.6.6.6
Subtract from .
Step 5.2.6.6.7
Add and .
Step 5.2.7
Simplify the denominator.
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Step 5.2.7.1
Multiply by .
Step 5.2.7.2
Apply the distributive property.
Step 5.2.7.3
Multiply by .
Step 5.2.7.4
Subtract from .
Step 5.2.7.5
Add and .
Step 5.2.7.6
Add and .
Step 5.2.8
Reduce the expression by cancelling the common factors.
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Step 5.2.8.1
Factor out of .
Step 5.2.8.2
Cancel the common factor of .
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Step 5.2.8.2.1
Factor out of .
Step 5.2.8.2.2
Cancel the common factor.
Step 5.2.8.2.3
Rewrite the expression.
Step 5.2.8.3
Cancel the common factor of .
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Step 5.2.8.3.1
Cancel the common factor.
Step 5.2.8.3.2
Rewrite the expression.
Step 5.3
Evaluate .
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Step 5.3.1
Set up the composite result function.
Step 5.3.2
Evaluate by substituting in the value of into .
Step 5.3.3
Multiply the numerator and denominator of the fraction by .
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Step 5.3.3.1
Multiply by .
Step 5.3.3.2
Combine.
Step 5.3.4
Apply the distributive property.
Step 5.3.5
Simplify by cancelling.
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Step 5.3.5.1
Cancel the common factor of .
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Step 5.3.5.1.1
Cancel the common factor.
Step 5.3.5.1.2
Rewrite the expression.
Step 5.3.5.2
Cancel the common factor of .
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Step 5.3.5.2.1
Cancel the common factor.
Step 5.3.5.2.2
Rewrite the expression.
Step 5.3.6
Simplify the numerator.
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Step 5.3.6.1
Apply the distributive property.
Step 5.3.6.2
Multiply by .
Step 5.3.6.3
Multiply by .
Step 5.3.6.4
Add and .
Step 5.3.6.5
Subtract from .
Step 5.3.6.6
Add and .
Step 5.3.7
Simplify the denominator.
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Step 5.3.7.1
Apply the distributive property.
Step 5.3.7.2
Multiply by .
Step 5.3.7.3
Multiply by .
Step 5.3.7.4
Subtract from .
Step 5.3.7.5
Add and .
Step 5.3.7.6
Add and .
Step 5.3.8
Cancel the common factor of .
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Step 5.3.8.1
Cancel the common factor.
Step 5.3.8.2
Divide by .
Step 5.4
Since and , then is the inverse of .