17.) It's a square, so the sides are even (or equal to each other). Set this up like so:
10x = 6x + 8
Eliminate what you can, in this case 6x. Do this:
10x - 6x and 6x - 6x.
You are left with 4x = 8, so divide each side by four, and this is what you get:
x = 2