Precalculus Examples

Find the Inverse f(x) = cube root of x/8-4
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
Add to both sides of the equation.
Step 3.3
To remove the radical on the left side of the equation, cube both sides of the equation.
Step 3.4
Simplify each side of the equation.
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Step 3.4.1
Use to rewrite as .
Step 3.4.2
Simplify the left side.
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Step 3.4.2.1
Simplify .
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Step 3.4.2.1.1
Multiply the exponents in .
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Step 3.4.2.1.1.1
Apply the power rule and multiply exponents, .
Step 3.4.2.1.1.2
Cancel the common factor of .
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Step 3.4.2.1.1.2.1
Cancel the common factor.
Step 3.4.2.1.1.2.2
Rewrite the expression.
Step 3.4.2.1.2
Simplify.
Step 3.4.3
Simplify the right side.
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Step 3.4.3.1
Simplify .
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Step 3.4.3.1.1
Use the Binomial Theorem.
Step 3.4.3.1.2
Simplify each term.
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Step 3.4.3.1.2.1
Multiply by .
Step 3.4.3.1.2.2
Raise to the power of .
Step 3.4.3.1.2.3
Multiply by .
Step 3.4.3.1.2.4
Raise to the power of .
Step 3.5
Solve for .
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Step 3.5.1
Multiply both sides of the equation by .
Step 3.5.2
Simplify both sides of the equation.
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Step 3.5.2.1
Simplify the left side.
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Step 3.5.2.1.1
Cancel the common factor of .
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Step 3.5.2.1.1.1
Cancel the common factor.
Step 3.5.2.1.1.2
Rewrite the expression.
Step 3.5.2.2
Simplify the right side.
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Step 3.5.2.2.1
Simplify .
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Step 3.5.2.2.1.1
Apply the distributive property.
Step 3.5.2.2.1.2
Simplify.
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Step 3.5.2.2.1.2.1
Multiply by .
Step 3.5.2.2.1.2.2
Multiply by .
Step 3.5.2.2.1.2.3
Multiply by .
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
Simplify each term.
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Step 5.2.3.1
Simplify each term.
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Step 5.2.3.1.1
Rewrite as .
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Step 5.2.3.1.1.1
Factor the perfect power out of .
Step 5.2.3.1.1.2
Factor the perfect power out of .
Step 5.2.3.1.1.3
Rearrange the fraction .
Step 5.2.3.1.2
Pull terms out from under the radical.
Step 5.2.3.1.3
Combine and .
Step 5.2.3.2
Use the Binomial Theorem.
Step 5.2.3.3
Simplify each term.
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Step 5.2.3.3.1
Apply the product rule to .
Step 5.2.3.3.2
Rewrite as .
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Step 5.2.3.3.2.1
Use to rewrite as .
Step 5.2.3.3.2.2
Apply the power rule and multiply exponents, .
Step 5.2.3.3.2.3
Combine and .
Step 5.2.3.3.2.4
Cancel the common factor of .
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Step 5.2.3.3.2.4.1
Cancel the common factor.
Step 5.2.3.3.2.4.2
Rewrite the expression.
Step 5.2.3.3.2.5
Simplify.
Step 5.2.3.3.3
Raise to the power of .
Step 5.2.3.3.4
Apply the product rule to .
Step 5.2.3.3.5
Rewrite as .
Step 5.2.3.3.6
Raise to the power of .
Step 5.2.3.3.7
Combine and .
Step 5.2.3.3.8
Cancel the common factor of .
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Step 5.2.3.3.8.1
Factor out of .
Step 5.2.3.3.8.2
Cancel the common factor.
Step 5.2.3.3.8.3
Rewrite the expression.
Step 5.2.3.3.9
Multiply by .
Step 5.2.3.3.10
Combine and .
Step 5.2.3.3.11
Raise to the power of .
Step 5.2.3.3.12
Cancel the common factor of .
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Step 5.2.3.3.12.1
Factor out of .
Step 5.2.3.3.12.2
Cancel the common factor.
Step 5.2.3.3.12.3
Rewrite the expression.
Step 5.2.3.3.13
Multiply by .
Step 5.2.3.3.14
Raise to the power of .
Step 5.2.3.4
Apply the distributive property.
Step 5.2.3.5
Simplify.
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Step 5.2.3.5.1
Cancel the common factor of .
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Step 5.2.3.5.1.1
Cancel the common factor.
Step 5.2.3.5.1.2
Rewrite the expression.
Step 5.2.3.5.2
Multiply by .
Step 5.2.3.5.3
Multiply by .
Step 5.2.3.5.4
Multiply by .
Step 5.2.3.6
Simplify each term.
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Step 5.2.3.6.1
Rewrite as .
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Step 5.2.3.6.1.1
Factor the perfect power out of .
Step 5.2.3.6.1.2
Factor the perfect power out of .
Step 5.2.3.6.1.3
Rearrange the fraction .
Step 5.2.3.6.2
Pull terms out from under the radical.
Step 5.2.3.6.3
Combine and .
Step 5.2.3.7
Rewrite as .
Step 5.2.3.8
Expand using the FOIL Method.
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Step 5.2.3.8.1
Apply the distributive property.
Step 5.2.3.8.2
Apply the distributive property.
Step 5.2.3.8.3
Apply the distributive property.
Step 5.2.3.9
Simplify and combine like terms.
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Step 5.2.3.9.1
Simplify each term.
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Step 5.2.3.9.1.1
Multiply .
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Step 5.2.3.9.1.1.1
Multiply by .
Step 5.2.3.9.1.1.2
Raise to the power of .
Step 5.2.3.9.1.1.3
Raise to the power of .
Step 5.2.3.9.1.1.4
Use the power rule to combine exponents.
Step 5.2.3.9.1.1.5
Add and .
Step 5.2.3.9.1.1.6
Multiply by .
Step 5.2.3.9.1.2
Rewrite as .
Step 5.2.3.9.1.3
Cancel the common factor of .
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Step 5.2.3.9.1.3.1
Factor out of .
Step 5.2.3.9.1.3.2
Cancel the common factor.
Step 5.2.3.9.1.3.3
Rewrite the expression.
Step 5.2.3.9.1.4
Move to the left of .
Step 5.2.3.9.1.5
Cancel the common factor of .
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Step 5.2.3.9.1.5.1
Factor out of .
Step 5.2.3.9.1.5.2
Cancel the common factor.
Step 5.2.3.9.1.5.3
Rewrite the expression.
Step 5.2.3.9.1.6
Multiply by .
Step 5.2.3.9.2
Subtract from .
Step 5.2.3.10
Apply the distributive property.
Step 5.2.3.11
Simplify.
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Step 5.2.3.11.1
Cancel the common factor of .
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Step 5.2.3.11.1.1
Factor out of .
Step 5.2.3.11.1.2
Cancel the common factor.
Step 5.2.3.11.1.3
Rewrite the expression.
Step 5.2.3.11.2
Multiply by .
Step 5.2.3.11.3
Multiply by .
Step 5.2.3.12
Simplify each term.
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Step 5.2.3.12.1
Rewrite as .
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Step 5.2.3.12.1.1
Factor the perfect power out of .
Step 5.2.3.12.1.2
Factor the perfect power out of .
Step 5.2.3.12.1.3
Rearrange the fraction .
Step 5.2.3.12.2
Pull terms out from under the radical.
Step 5.2.3.12.3
Combine and .
Step 5.2.3.13
Apply the distributive property.
Step 5.2.3.14
Cancel the common factor of .
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Step 5.2.3.14.1
Factor out of .
Step 5.2.3.14.2
Cancel the common factor.
Step 5.2.3.14.3
Rewrite the expression.
Step 5.2.3.15
Multiply by .
Step 5.2.4
Simplify by adding terms.
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Step 5.2.4.1
Combine the opposite terms in .
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Step 5.2.4.1.1
Add and .
Step 5.2.4.1.2
Add and .
Step 5.2.4.1.3
Subtract from .
Step 5.2.4.1.4
Add and .
Step 5.2.4.1.5
Add and .
Step 5.2.4.1.6
Add and .
Step 5.2.4.2
Subtract from .
Step 5.2.4.3
Combine the opposite terms in .
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Step 5.2.4.3.1
Add and .
Step 5.2.4.3.2
Add and .
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
Simplify each term.
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Step 5.3.3.1
Factor out of .
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Step 5.3.3.1.1
Factor out of .
Step 5.3.3.1.2
Factor out of .
Step 5.3.3.1.3
Factor out of .
Step 5.3.3.1.4
Factor out of .
Step 5.3.3.1.5
Factor out of .
Step 5.3.3.1.6
Factor out of .
Step 5.3.3.1.7
Factor out of .
Step 5.3.3.2
Reduce the expression by cancelling the common factors.
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Step 5.3.3.2.1
Reduce the expression by cancelling the common factors.
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Step 5.3.3.2.1.1
Cancel the common factor.
Step 5.3.3.2.1.2
Rewrite the expression.
Step 5.3.3.2.2
Divide by .
Step 5.3.3.3
Make each term match the terms from the binomial theorem formula.
Step 5.3.3.4
Factor using the binomial theorem.
Step 5.3.3.5
Pull terms out from under the radical, assuming real numbers.
Step 5.3.4
Combine the opposite terms in .
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Step 5.3.4.1
Subtract from .
Step 5.3.4.2
Add and .
Step 5.4
Since and , then is the inverse of .