1)(c2-d2)/(bc-bd)=((c-d)(c+d))/(b(c-d)=(c+d)/b
2)(3x2-27)/(3x-x2)=(3(x2-9))/(x(3-x))=(3(x-3)(x+3))/(x(-(x-3))=-(3x+9)/x
1)(c2-d2)/(bc-bd)=((c-d)(c+d))/(b(c-d)=(c+d)/b
2)(3x2-27)/(3x-x2)=(3(x2-9))/(x(3-x))=(3(x-3)(x+3))/(x(-(x-3))=-(3x+9)/x