Question

X平方减去Y平方加X加3Y减2 做十字相乘 怎么拆啊

Answer 1

令X=0

-Y^2+3Y-2=-(Y-1)(Y-2)

令Y=0

X^2+X-2=(X+2)(X-1)

X平方减去Y平方加X加3Y减2= (X+Y-1)(X-Y+2)