Answer:
7
Step-by-step explanation:

I hope it helped you
What you have written down is correct, x=-3
For this case we must find the inverse of the following function:

We follow the steps below:
Replace f(x) with y:

We exchange the variables:

We solve for "y":

Multiply by -2 on both sides of the equation:

We raise both sides of the equation to the square to eliminate the radical:

We subtract 3 from both sides of the equation:

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

Answer:
question 3 = $150 because 50% is one half of 100% so 300/2 = 150