已知m-n-4的绝对值+(mn+1)的平方=0,求(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值

2024-12-23 04:45:14
推荐回答(2个)
回答1:

∵丨m-n-4丨≥0,(mn+1)²≥0
又丨m-n-4丨+(mn+1)²=0
∴丨m-n-4丨=0,(mn+1)²=0
∴m-n-4=0, mn+1=0
∴m-n=4 ①, mn= -1②,

把(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的括号去掉,并且合并同类项,此式可整理为:3m-3n-6mn=3(m-n)-6mn
再将①、②代入上式,可得
(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=3×4+6=18

回答2:

相信我 肯定16