Question

(x的二次方+4x+3）（x的二次方+12x+35）+15因式分解

Answer 1

(x的二次方+4x+3）（x的二次方+12x+35）+15

=(x+1)(x+3)(x+5)(x+7)+15

=[(x+1)(x+7)][(x+3)(x+5)]+15

=(x²+8x+7)(x²+8x+15)+15

=(x²+8x)²+22(x²+8x)+105+15

=(x²+8x)²+22(x²+8x)+120

=(x²+8x+12)(x²+8x+10)

=(x+2)(x+6)(x²+8x+10)