SOLUTION: Find the value of {{{f^-1}}}8, when f(R)=R is defined by f(x+5)={{{x^3+7x+8}}}

Algebra ->  Functions -> SOLUTION: Find the value of {{{f^-1}}}8, when f(R)=R is defined by f(x+5)={{{x^3+7x+8}}}      Log On


   

Question 1037858: Find the value of f%5E-18, when f(R)=R is defined by f(x+5)=x%5E3%2B7x%2B8
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
Move back by five units on x, in the function.
f%28x%29=%28x-5%29%5E3%2B7%28x-5%29%2B8, simplify, and then try to find the inverse of f.

Try restating this as (x-5)^3+7(x-5)+8=y; and then after simplifying, switch x and y. TRY to solve for y in terms of x. If this is possible, then you found the inverse. DOES THIS WORK? You'll just have to try it to see if it works or not.