how do i solve for x? is it possible with this?

Note that you don't need to multiply out to solve for x because you already have two factors.

For the second one, -2x² +7x + 15 =0, you could either use the quadratic formula, or do the following:

Divide through by -2

x² - (7/2)*x + (15/2) = 0

This factors as:

(x + 3/2)*(x - 10/2) = 0  or  (x + 3/2)*(x - 5) = 0

This gives the two values for x as x = -3/2 and x = 5