плиз помогите 7 и 8 пример

(b-2)/(2(b-3)) - (b-1)/(3(b-3)) = (3(b-2)-2(b-1))/(6(b-3)) = (3b-6-2b+2)/(6(b-3)) = (b-4)/(6b-18)

4/((x-3)(x+3)) -2/(x(x+3)) = (4x-2(x-3))/(x(x-3)(x+3)) = (4x-2x+6)/(x(x-3)(x+3)) = (2(x+3))/(x(x-3)(x+3)) = 2/(x(x-3))