в) 12x^2 = 70+13x+(2x-1)(x+6)
0 = -12x^2 + 70 + 13x + 2x^2 + 12x -x - 6
-10x^2 + 24x + 64 = 0
-5x^2 + 12x + 32 = 0
D=144+640=784=28^2
x1=(-12-28)/(-10) = 4 x2=(-12+28)/(-10) = -1.6
г) 4x^2 = 19x - 21 + (2x-1)(x+5)
0 = -4x^2 + 19x - 21 + 2x^2 + 10x - x - 5
-2x^2 + 28x - 26 =0
-x^2 + 14x - 13 =0
D= 144 = 12^2
x1=(-14-12)/(-2) = 13 x2=(-14+12)/(-2) = 1
А какие там ответы?