1.（2x-y+3)(2x-y+1)-15

题目

1.（2x-y+3)(2x-y+1)-15
2.x平方-3xy+2y平方+y-1
3.(x平方+x立方-2)/(x-1)

答案

1.=(2x-y)2+4(2x-y)-12
=(2x-y)2+4(2x-y)+4-16
=(2x-y+2)2-16
=(2x-y+2+4)(2x-y+2-4)
=(2x-y+6)(2x-y-2)
2.
3.
实在不会了,好难呢