1) 7с²+13с-2 / с-7с² = 7с²-с+14с-2 / с-7с² = с(7с-1)+2(7с-1) / -с(7с-1) = (7с-1)(с+2) / -с(7с-1) = - с+2 / с
2) 7y²-y / 2-13y-7y² = -y(1-7y) / 2-14y+y-7y² = -y(1-7y) / 2(1-7y)+y(1-7y) = -y(1-7y) / (1-7y)(2+y) = - y / 2+y = - 8 / 2+8 = -8/10 = -0,8
3) 1-6x+y-6xy / 36x²-12x+1 = (1-6x)+y(1-6x) / (6x-1)² = -(6x-1)(1+y) / (6x-1)² = - 1+y / 6x-1