|3x|=9
3x=9 -3x=9
X=9/3 x=9/-3
x=3 x=-3
Whenever you have an absolute value sign you have to find both the positive and the negative because they didnt signs into the equation but sometimes a question will ask for strictly the positive value or the negative value but if its not stated, find both.
For the square root of a negative number, you would have to get into imaginary numbers. If you haven't learned about it yet, then the answer would be no real solutions. But if you have, here's how to solve it:
First, identify that 9 x 3 = 27. To after taking the square root, you will get 3√3 (Since the square root of 9 is 3 and there's no square root of 3, so leave it in the √)
However, since it is a negative number, you will have to include the letter i in the answer. i represents the imaginary part of it since you can't have a negative number in the square root.
So your answer will look like 3i√3.