9x平方成(x-1)平方-30x乘(x-1)-56得多少?(x平方+4x+3)(x平方+12x+35)得多少?
问题描述：
9x平方成(x-1)平方-30x乘(x-1)-56得多少?(x平方+4x+3)(x平方+12x+35)得多少?
答
(1) 9x^2*(x-1)^2-30x(x-1)-56 =[3x(x-1)]^2-2*3x(x-1)*5+25-81 =[(3x(x-1)-5]^2-9^2 =[3x(x-1)-5-9][3x(x-1)-5+9] =(3x^2-3x-14)(3x^2-3x+6) =3(3x^2-3x-14)(x^2-x+2) (2) (x^2+4x+3)(x^2+12x+35) =(x+3)(x+1)(x+7)...