1.75/30-40
получается
1.75/-10
ответ:-0.175
6х+2х-9х=-12+14-1
-1х=1
х=1
17.5
1) х² + bx - ax - ab = x(x+b) - a(x+b) = (x+b)(x-a)
2) x² - cx + bx - bc = x(x-c) + b(x-c) = (x-c)(x+b)
3) z² + zx - zk - xk = z(z+x) - k(z+x) = (z+x)(z-k)
4) y² + my - km - ky = y² + my - ky - km = y(y+m) - k(y+m) = (y+m)(y-k)