Question

If F(x) = 4x + 7, which of the following is the inverse of Fx)?

Answer 1

Answer:

$f^{-1}$(x) = $\frac{x-7}{4}$

Step-by-step explanation:

Let y = f(x) and rearrange making x the subject, that is

y = 4x + 7 ( subtract 7 from both sides )

y - 7 = 4x ( divide both sides by 4 )

$\frac{y-7}{4}$ = x

Change y back into terms of x, hence

$f^{-1}$(x) = $\frac{x-7}{4}$

Answer 2

Answer: y=(x/4)-(7/4)

Step-by-step explanation:

The easiest way to solve for an inverse is to switch the x and y variables. For F(x)=4x+7, which is essentially equal to y=4x+7, you switch the x and y variables and get x=4y+7. You then solve for the y variable, as shown below, to obtain the inverse of the equation.

x=4y+7

4y=x-7

y=(x/4)-(7/4)