中二的因式分解的几道题谁会?1.因式分解xy+1-x-y2.因式分解a^4-13.因式分解(3x-y)²-(3x+y)²
6个回答
1、xy+1-x-y=(x-1)(y-1)
2、a^4-1=(a^2+1)(a^2-1)=(a^2+1)(a+1)(a-1)
3、(3x-y)^2-(3x+y)^2=[(3x-y)+(3x+y)][(3x-y)-(3x+y)]=6x*(-2y)= -12xy
4、m=20xy ,则原式=(2x+5y)^2 ；m= -20xy,则原式=(2x-5y)^2
5、16x^3-2y^3=2[(8x)^3-y^3]=2(8x-y)[(8x)^2+(8x)y+y^2]=2(8x-y)(64x^2+8xy+y^2)
6、ax^3+8y^3=(3x+2y)(bx^2-6xy+4y^2)=3bx^3+(2b-18)x^2y+8y^3 ,
所以 3b=a,且 2b-18=0 ,解得 a=27,b=9 .
7、x^2-2x-24=(x+4)(x-6)
8、5x^2+11x-12=(x+3)(5x-4)
9、5x^2-14xy-3y^2=(x-3y)(5x+y)
