3. 7+8a-12a2=
4. 15x2+7xy-4y2=
5. 6x2-5x-6=
6. 12x2+32xy-35y2=
7. 6x2+31x-105=
8. 12x2+11xy-15y2=
9. (x2+2)2-9x2=
10. x2-(a+1)x+a=
11. x2-y2+3x-y+2=(x+y)(x-y)+3x-y+2=(x+y+2)(x-y+1)
12. x2-xy-6y2+4x-7y+3=(x+2y)(x-3y)+4x-7y+3=(x+2y+3)(x-3y+1)
13. 6x2-7xy-3y2-x+7y-2=(2x-3y)(3x+y)-x+7y-2=(2x-3y+1)(3x+y-2)
14. abx2-acx+b2x-bc=(ax+b)(bx-c)
15. x3+3x2+x+3=(x2+1(x+3)
16. x4-2x2y-3y2+8y-4=x4-2x2y-(3y-2)(y-2)=(x2-3y+2)(x2+y-2)
以上全是十字相乘的題,壹定要學會呀,這是高中的基礎.
註:x2,y2均表平方,簡單的題答案自已做就行了,難分解的我已經給出妳作案了.