Решите уравнения ; ( 16б) (4x-3)(5x+8)=0 (-7x+4)(8x-9)=0

Question

Решите уравнения ; ( 16б)
(4x-3)(5x+8)=0
(-7x+4)(8x-9)=0

Comments

Это система уравнений или два отдельных уравнения?

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2 отдельных

Answer 1

(4x-3)(5x+8)=0
20х^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

Comments

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