Решите уравнения:
а) [tex]12-6 x^{2} =(2x+3)(5-3x)[/tex]
б) [tex](x+7)(x-8)-(x-9)(x+10)=0[/tex]

a) 12 - 6x² = (2x +3)(5-3x)12- 6x² = 10x - 6x² + 15 - 9x12- 6x² = -6x² + x + 15-12x² + x - 3 = 0 | * (-1)12x² - x + 3 = 0D = 1 - 4*12*3 = 1 - 144 = -143 < 0, корней нетб)(x+7)(x-8) - (x-9)(x+10) = 0(x²- 8x + 7x - 56) - (x² + 10x - 9x - 90) = 0(x² - x - 56) - (x² + x - 90) = 0x² - x - 56 - x² - x + 90 = 0-2x + 34 = 0-2x = -34x = -34/-2x = 17