inverse of f(x)=2x^3-5

Question

so ive got 

 

y=2x^3-5

you switch the x and y:

x=2y^3-5

move the five to the opposite side:

x+5=2y^3

and divide by two:

x+5/2=y^3

 

im not sure about the last step but if someone could help me finish this it would be much appreciated, thank u thank u :^)

Answer 1

f(x) = 2x³ - 5

x = 2(f^-1(x))³  - 5

x + 5 = 2(f^-1(x))³

(x + 5)/2 = (f^-1(x))³

³√[(x + 5) / 2] = f^-1(x)