已知mn (m n)=2,求(3m-5mn 3n) (-m 3mn-n)的值
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![已知mn (m n)=2,求(3m-5mn 3n) (-m 3mn-n)的值](/uploads/image/f/4222670-14-0.jpg?t=%E5%B7%B2%E7%9F%A5mn+%28m+n%29%3D2%2C%E6%B1%82%283m-5mn+3n%29+%28-m+3mn-n%29%E7%9A%84%E5%80%BC)
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,
2(mn+m)-[-(3n-mn)-m]+mn =2mn+2m+3n-mn+m+mn =2mn+3m+2n =2mn+3(m+n) ∵m+n=3,mn=-2 ∴2(mn+m)-[-(3n-m
3m-5mn+3n/(-m)+3mn-n=【3(m+n)-5mn】/【3mn-(m+n)】=【3-5mn/(m+n)】/【3mn/(m+n)-1】=【3-5x2】/【3x2-1】=-7/5
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
答:mn/(m+n)=2分子分母同除以mn得:1/(1/n+1/m)=21/m+1/n=1/2(3m-5mn+3n)/(-m+3mn-n)分子分母同除以mn得:=(3/n-5+3/m)/(-1/n+3
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+n)]/[-(m
|m+n-2|+(mn+3)^=0必然M+N-2=0MN+3=0即M+N=2,MN=-3所以2(m+n)-2[mn+(m+n)]+3[2(m+n)-3mn]=2*2-2{-3+2]+3[2*2-3*(
m²-mn=15==>3m²-3mn=45(1)mn-n²=-6==>2mn-2n²=-12(2)(1)式+(2)式==>3m²-mn-2n²
-MN(M^2N^5-MN^3-N)=-(-6)^3+(-6)^2-(-6)=258
-2mn+2m+3n-3mn-2n+2m-4n-m-mn=-6mn+3m-3n=-6mn+3(m-n)=6+9=15
m²+(n-mn)²+2mn-2m²n=m²+n²-2mn²+m²n²+2mn-2m²n=m²+2m
m+n-2=0;mn+3=0;3(m+n)-2【mn+(m+n)】-3【2(m+n)-3mn=3×2-2(-3+2)-3(2×2+9)=6+2-39=-31;很高兴为您解答,skyhunter002为
原式=-2mn+2m+3n-3mn-2n+2n-m-4n-mn=-6mn+m-n=-6×2+4=-8
=(m^2-mn)+2(m^2-n^2)=(m^2-mn)+2(m^2-mn)+2(mn-n^2)题目条件打错了,自己代入一下
知m-n=7,mn=2求5n-3mn+5m+2(m+n)²=(m-n)²+4mn=49+8=57m+n=正负根号575n-3mn+5m+2=5n+5m-3mn+2=5(m+n)-3
∵原式=-3(2n-mn)+2(mn-3m)=-6(m+n)+5mn∵m+n=-3,mn=2∴原式=-6·-3+5·2=28
(-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
3(2n-mn)+2(mn+3m)=6n-3mn+2mn+6m=6(m+n)-mn=6*-3-2=-20
2(mn-3m)-3(2n-mn)=2mn-6m-6n+3mn=2mn+3mn-6(m+n)=32