(x ^2 +4x+3)(x ^ 2+12x+35)+15 =(x+1)(x+3)(x+5)(x+7)+15 =(x+1)(x+7) (x+3) (x+5)+ 15 =(x ^2 +8x+7)(x ^ 2+8x+15)+15 =(x ^ 2+8x)^2+22(x ^ 2+8x)+120 =(x ^2 +8x+10)(x ^ 2+8x+12) =(x ^2 +8x+10)(x +2) (x +6)
(x平方+4x+3)(x平方+12x+35)+15因式分解
(x ^2 +4x+3)(x ^ 2+12x+35)+15 =(x+1)(x+3)(x+5)(x+7)+15 =(x+1)(x+7) (x+3) (x+5)+ 15 =(x ^2 +8x+7)(x ^ 2+8x+15)+15 =(x ^ 2+8x)^2+22(x ^ 2+8x)+120 =(x ^2 +8x+10)(x ^ 2+8x+12) =(x ^2 +8x+10)(x +2) (x +6)