Question

求解几道因式分解

T T
第五题呢、

Answer 1

1.原式=(x^2-y^2)+(x^3-y^3)
=(x+y)(x-y)+(x-y)(x^2+xy+y^2)
=(x-y)(x^2+xy+y^2+x+y)
2.原式=4x^2+(6-4y)x+y^2-3y-10
=4x^2+(6-4y)x+(y-5)(y+2)
=(2x-y+5)（2x-y-2)
3.原式=[(a+1)(a+7)][(a+3)(a+5)]+15
=(a^2+8a+7)(a^2+8a+15)+15
=(a^2+8a+7)^2+8(a^2+8a+7)+15
=(a^2+8a+7+3)(a^2+8a+7+5)
=(a^2+8a+10)(a+2)(a+6)
4.原式=a^2-ab+2a-6b(b+1)
=a^2+(2-b)a-6b(b+1)
=(a+2b+2)(a-3b)
6.原式=(a+1)^3+1
=(a+2)[(a+1)^2+1-a-1]
=(a+2)(a^2+a+1)
7.计算出原式的判别式＜0，即便在实数范围内也无法分解