Răspuns:
a) Numitor comun 6
3(3x-2) - 2(x-4) = 30
9x-6-2x+8=30
7x+2=30
7x=28
x=4
b)E1(x)=x^2(x+3) - 4(x+3)
E1(x)=(x+3)(x^2 - 4)
E1(x)=(x+3)(x-2)(x+2)
E2(x)=x^2(x+2) - 9(x+2)
E2(x)=(x+2)(x^2 - 9)
E2(x)=(x+2)(x+3)(x-3)
x^3 + 3x^2 - 4x - 12 - x^3 - 2x^2 + 9x + 18 =
x^2 + 5x + 6 =
x^2 + 2x + 3x + 6 =
x(x+2) + 3(x+2) =
(x+2)(x+3)
