I'm having trouble with this. i know it's simple, but I'm honestly blanking out on how to do this:

2 equations:

X = 12L - 0.75L^2

A = 24L - 2.25L^2

What does L equal when X and A intersect?

I know this means when X = A, which is 12L - 0.75L^2 = 24L - 2.25L^2

The answer is X = A at 8 but how do I find this?