因式分解:(m-n)²+2（n-m）=_______ 因式分解：x²-y²+6y-9=______

因式分解:(m-n)²+2（n-m）=_______ 因式分解：x²-y²+6y-9=______
因式分解:(m-n)²+2（n-m）=_______ 因式分解：x²-y²+6y-9=______

因式分解:(m-n)²+2（n-m）=_______ 因式分解：x²-y²+6y-9=______
(m-n)²+2（n-m）=_______
= (m-n)² -2 (m-n)
= (m-n-2) (m-n)
x²-y²+6y-9=______
= x²-(y²-6y+9)
= x²- (y-3)²
= (x+y-3) (x-y+3)

(m-n)²+2（n-m）=（n-m）(n-m+2)
x²-y²+6y-9=x²-(y-3)²=（x+y-3）(x-y+3)

2.(x+y-3)(x-y+3)
1.(n-m+2)(-m+n)