Question

If f(x) = 2x +4, which of the following is the inverse of f(x)

Answer 1

If f(x)=2x+4 then the inverse is x=(2/7)f(x)+4
Now just solve for the new f(x)
(2/7)f(x)=x-4
f(x)=(7/2)(x-4)
ANSWER: A

Answer 2

Explanation:

let y = f(x)

y = 2x/7 + 4

2x/7 = y - 4

x/7 = (y - 4)/2

x = 7(y - 4)/2

therefore, f^-1(x) = 7(x - 4)/2 (Option A)

Topic: Functions

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