20. 5x2 – 3x - 2 = 0

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

x = [3 ± √((-3)^2 - 4*5*(-2))] / (2*5)

x = [3 ± √49] / 10

x = (3 ± 7) / 10

x1 = 10/10 = 1, x2 = -4/10 = -2/5