(m+n)² ( m-n)² mn 的等量关系-搜答案-百度作业网

由于:mn/(m+n)=2则有：mn=2(m+n)则:原式=(3m+3n-5mn)/(-m-n+3mn)=[3(m+n)-5mn]/[-(m+n)+3mn]=[3(m+n)-10(m

(2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)先去括号=2mn+2m+3n-3mn-2n+2m-m-4n-mn合并同类项=-2mn+3m-3n=-2mn+3(m-n)把m-n=2,

原式=（2m-m）/m=m/m=1~

解（-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn）=-2mn+2m+3n-3mn-2n+2m-m-4n-mn=-2mn-3mn-mn+2m+2m-m+3n-2n-4n=-6mn+3

=m(m+n)/(m-n)×m/(m+n)-n²/(m-n)=m²/(m-n)-n²/(m-n)=(m²-n²)/(m-n)=(m+n)(m-n)/(

(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=-2mn+2m+3n-3mn-2n+2m-m-4n-mn=(-2mn-3mn-mn)+(2m+2m-m)+(3n-2n-4n)=-

因为m-mn=21,mn-n=15,所以：m-n=(m-mn)+(mn-n)=21+15=36m-2mn+n=(m-mn)-(mn-n)=21-15=6希望能都帮到你,追问：对不起啊.我把题发错了,m

m(m-n)(n+1)

m(m+n)(m-n)-m(m+n)^2=m(m+n)[(m-n)-(m+n)]=m(m+n)(-2n)=-2mn(m+n)=-2*(-1/2)*1=1

m/(m-n)-n/(m+n)+mn/(m^2-n^2)=[m(m+n)-n(m-n)]/(m+n)(m-n)+mn/(m+n)(m-n)=(m^2+mn-mn+n^2)/(m+n)(m-n)+mn/

-2mn+2m+3n-3mn-2n+2m-4n-m-mn=-6mn+3m-3n=-6mn+3(m-n)=6+9=15

根据题意绝对值和完全平方非负所以mn-1=0m-n-2=0mn=1m-n=2（-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=-2mn+2m+3n-3mn-2n+2m-m-4n-m

mn(m-n)-(n-m)=mn(m-n)+(m-n)=(mn+1)(m-n)

原式=-2mn+2m+3n-3mn-2n+2n-m-4n-mn=-6mn+m-n=-6×2+4=-8

（m-n）（m+n）再答：两个相乘再问：求完整过程……再问：求完整过程……再问：我都用平放差公式算了一页草稿了……再答：等下，我给你写再答：再答：记得采纳哦，亲～再问：谢谢>_

m的平方n-mn的平方

m²n-mn²=mn(m-n)

先把每个分母变成乘积形式第一个m²-mn=m(m-n)第二个n²-mn=n(m-n)第三个m²-n²=(m+n)(m-n)所以最简公分母就是mn(m+n)(m-

m²n(m-n)-4mn(n-m)

m²n(m-n)-4mn(n-m)=m²n(m-n)+4mn(m-n)=mn(m+4)(m-n)

已知mn=-1,m-n=4则(-2mn+m+n)-(3mn+5n-5m)-(m+4n-3mn)=-2mn+m+n-3mn-5n+5m-m-4n+3mn=-2mn+5m-8n=2+20-3n=22-3n

(-m-4n-mn)-(2mn-2m-3n)-(3mn+2n-2m)=-m-4n-mn-2mn+2m+3n-3mn-2n+2m=3m-3n-6mn=3(m-n)-6mn=3×3-6×(-3)=9+18