Решите уравнения; (16 б)

(4x-3) (5x+8) = 0

(-7x+4) (8x-9) = 0

(4x-3) (5x+8) = 0

20 х^2 + 32x - 15x - 24 = 0

20x^2 + 17x - 24 = 0

D = 289 + 1920 = 2209

x1 = (-17 + 47) / 40 = 3/4 = 0.75

x2 = (-17 - 47) / 40 = - 1.6

(-7x+4) (8x-9) = 0

-56x^2 + 63x + 32x - 36 = 0

-56x^2 + 95x - 36 = 0

D = 9025 - 8064 = 961

x1 = (-95 + 31) / 112 = 64/112 = 4/7

x2 = (-95 - 31) / 112 = - 1.125