Help me answer this question please

Question

asked Mar 20, 2020 143k views

1 Answer

Xiao Liang · Answer 1 · 2020-03-24T22:50:55+0000

For this case we must find the inverse of the following function:

f (x) = x ^ 2 + 7

For this we follow the steps below:

Replace f(x) with y:

y = x ^ 2 + 7

We exchange the variables:

x = y ^ 2 + 7

We solve the equation for "y", that is, we clear "y":

y^ 2 + 7 = x

We subtract 7 on both sides of the equation:

y ^ 2 = x-7

We apply square root on both sides of the equation to eliminate the exponent:

$y = \pm\sqrt {x-7}$

We change y by
$f ^ {- 1} (x):$

$f ^ {- 1} (x) =\pm\sqrt {x-7}$

Answer;

Option A