Question

分解(x+1)(x+3)(x+5)(x+7)+15

Answer 1

(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+7)[(x^2+8x+7)+8]+15
=(x^2+8x+7)^2+8(x^2+8x+7)+15
=[(x^2+8x+7)+3][(x^2+8x+7)+5]
=(x^2+8x+10)(x^2+8x+12)
=(x^2+8x+10)(x+2)(x+6)
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=(x+4-2根号6）（x+4+2根号6）（x+2)(x+6)

Answer 2

(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).

Answer 3

=((x+1)*(x+7))*((x+3)*(x+5)+15
=(x^2+8x+7)*(x^2+8x+15)
=(x^2+8x)^2+22(x^2+8x)+120
=(x^2+8x+12)*(x^2+8x+10)
=(x+2)*(x+6)*(x+4-6^(1/2))(x+4+6^(1/2))
注:6^(1/2)=6开根号

Answer 4

牛鄙
你几年级啊