let's do B and C first
5x^3 − 4 = 74.125
5x^3 = 78.125
x^3 = 15.625
x = cuberoot(15.625) = 2.5
a) f(x)=5x^3 − 4 or
y = 5x^3 - 4
step1. Interchange the x and y variables
x = 5y^3 - 4
step2. Now solve this new equation for y
5y^3 = x + 4
y^3 = (x+4)/5
y = cuberoot [ (x+4)/5 ] or y = ( (x+4)/5 )^(1/3)
Use the function f(x)=5x^3 − 4 to answer the questions.
A: What is f^−1 (x)?
B: What should be done to find the value of x that makes f(x)=74.125?
C: For what value of x does f(x)=74.125?
1 answer
1 answer