186k views
1 vote
#15, how do you solve it?

#15, how do you solve it?-example-1

1 Answer

2 votes
You have to find the inverse of the function, then plug in -25 to that.

So:
First replace y with x and x with y
x=4(y+8)^2 - 9
Solve for y
x + 9 = 4(y+8)^2
(x + 9)/4 = (y+8)^2
Here square root both sides
sqrt((x + 9)/4) = y + 8
Subtract 8 from both sides
y = sqrt((x + 9)/4) - 8

Now plug in -25 in this equation
y = sqrt((-25 + 9)/4) - 8
solve
y = sqrt((-16 / 4)) - 8
Here, there is a negative number under the square root sign. So, -25 cannot be in the domain and the answer is D.
User Omiz
by
8.0k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories