哇、、 实在想不出
(2m-n)²-(3m+2n)²
就这道不会了
大哥大姐帮忙想想
哇、、 实在想不出
(2m-n)²-(3m+2n)²
就这道不会了
大哥大姐帮忙想想
(2m-n)²-(3m+2n)²
=(2m-n+3m+2n)(2m-n-3m-2n)
=(5m+n)(-m-3n)
=-(5m+n)(m+3n)
这是完全平方公式展开
你那还需要多加联系
根据平方差公式可得
=(2M-N-3M-2N)(2M-N+3M+2N)
=(-3M-3N)(5M+N)
=-(3M+3N)(5M+N)
(2m-n)²-(3m+2n)²
=(2m-n+3m+2n)(2m-n-3m-2n)
=(5m+n)(-m-3n)
=-(5m+n)(m+3n)
平方差公式
(2m-n+3m+2n)(2m-n-3m-2n)
=-(5m+n)(m+3n)
(2m-n)²-(3m+2n)²=(2m-n+3m+2n)(2m-n-3m-2n)
=(5m+n)(-m-3n)=-(5m+n)(m+3n)
(2m-n)²-(3m+2n)²
=(2m-n+3m+2n)(2m-n-3m-2n)
=(5m+n)(-m-3n)
=-(5m+n)(m+3n)
=(2m-n+3m+2n)(2m-n-3m-2n)
=(5m+n)(-m-3n)