The answer will be r = 9/2.
Here is how I got that answer:
First, we must simplify both sides of this equation.
-3/2r = -27/4
Next, we must multiply both sides by 2/(-3).
(2/-3) * (-3/2r) = (2/-3) * (-27/4)
Then we get the answer.
r = 9/2
I hope this helps! :>
