13. 2x2 + 3x - 2 = 0

Using the quadratic formula x = [-b ± √(b^2 - 4ac)] / 2a

x = [-3 ± √(3^2 - 4*2*(-2))] / (2*2)

x = [-3 ± √25] / 4

x = (-3 ± 5) / 4

x1 = 2/4 = 1/2, x2 = -8/4 = -2