How to solve this:

-3 √(6x+5) = -9

Answer key (2/3)

Do we use conjugate of -3 √(6x+5)? If so, what is the conjugate of -3 √(6x+5)?

example: The conjugate of (x + √y) is (x - √y).

I don't think the conjugate of -3 √(6x+5) is -3 √(6x-5) since the above example has 2 terms, that is x and √y while -3 √(6x+5) is only 1 term.

I don't know how to solve this. Please help.

Thanks.