a) $4(x+2)-7(x-3)+5(2x+1)=15$
$7x+34=15 --> x = \frac{-19}{7}$
b) $4x(3x-2)+(6x+2).(1-2x)=-15$
$12x^2-8x+(2x+2-12x^2)=-15$
$-6x=-17 ---> x = \frac{17}{6}$
c) $(x-5).(x+5)-x(x-3)=-27$
$(x^2-25)-(x^2-3x)=-27$
$3x-25=-27 --> x = \frac{-2}{3}$
d) $(2x+3).(x-4)+(x-2).(x-5)=(3x-5).(x-4)$...