分解因式:x^2-2xy-8y^2-2x+14y-3=____________
參考答案:x^2-2xy-8y^2
=(x+2y)(x-4y)
假设
a(x+2y)+b(x-4y)=-2x+14y
则
a+b=-2,2a-4b=14
解得:
a=1,b=-3
那么
x^2-2xy-8y^2-2x+14y-3
=(x+2y)(x-4y)+(x+2y)-3(x-4y)-3
=(x+2y)(x-4y+1)-3(x-4y+1)
=(x+2y-3)(x-4y+1)
分解因式:x^2-2xy-8y^2-2x+14y-3=____________
參考答案:x^2-2xy-8y^2
=(x+2y)(x-4y)
假设
a(x+2y)+b(x-4y)=-2x+14y
则
a+b=-2,2a-4b=14
解得:
a=1,b=-3
那么
x^2-2xy-8y^2-2x+14y-3
=(x+2y)(x-4y)+(x+2y)-3(x-4y)-3
=(x+2y)(x-4y+1)-3(x-4y+1)
=(x+2y-3)(x-4y+1)