m平方-m=3,n平方-n=3,求2m平方-mn 2m 2015值-搜答案-搜狗做题网

(m-n-3) 平方

(m-n-3)^2={(m-n)-3}^2=(m-n)^2-6(m-n)+9=m^2-2mn+n^2-6m+6n+9

m/(m-n)-n/(m+n)+2mn/(m²-n²)=[m(m+n)-n(m-n)+2mn]/(m²-n²)=(m²+n²)/(m

(3m+2n)^2-(2m-3n)^2=[(3m+2n)+(2m-3n)][(3m+2n)-(2m-3n)]=(3m+2n+2m-3n)(3m+2n-2m+3n)=(5m-n)(m+5n)

(m²-6mn+9n²)÷(m-3n)-(4m²-9n²)÷(2m-3n)=(m-3n)²÷(m-3n)-(2m-3n)(2m+3n)÷(2m-3n)

由题意得：n=2m²-3.①m=2n²-3.②m≠n①-②得：n-m=2(m+n)(m-n)∴n=-m.③∴2m³-2mn+2n³=2m³+2m

m/(m+n)+m/(m-n)-n²/((m²-n²)=(m²-mn+m²+mn-n²)/(m²-n²)=(2m&sup

m-3=0m^2-4mn+4n^2=0m=3(m-2n)^2=0n=3/2

|m-n|=n-m=-(m-n)所以m-n≤0m=±4,n=±3m-n≤0所以m=-4,n=±3则m+n=-7或-1所以【m+n】的平方=49或1

首先2m^2+3n^2-mn-3m^2-4n^2+mn+6=（2m^2-3m^3）+(3n^2-4n^2)+(mn-mn)+6=-m^2-n^2+6m^2+n^2=5,所以-m^2-n^2=-5所以,

因为m^2-n^2=6(m-n)(m+n)=63*(m+n)=6(m+n)=2学习愉快

原式=m/(mn)m/(m-n)-n^2/(m^2-n^2)=(m^2-mnm^2mn)/(m^2-n^2)-n^2/(m^2-n^2)=(2m^2-n^2)/(m^2-n^2)因为m/n=5/3,所

(2m-3n)²+24mn=(2m-3n)²(3x-2y+1)(3x+2y-1)=[3x-(2y-1)][3x+(2y-1)]=(3x)²-(2y-1)²=9x

原式=m/(m+n)+m/(m-n)-n^2/(m^2-n^2)=(m^2-mn+m^2+mn)/(m^2-n^2)-n^2/(m^2-n^2)=(2m^2-n^2)/(m^2-n^2)因为m/n=5

5(m+n)(m-n)-2(m+n)平方-3(m-n)平方=5m^2-5n^2-2m^2-4mn-2n^2-3m^2+6mn-3n^2=2mn

解析:m^2-3m=1n^2-3n=1则m^2-3m=n^2-3n解得m=n或m=3-n当m=n时m/n+n/m=2m=3-n时m/n+n/m=(m^2+n^2)/nm把m=3-n代入得=-[2(n^

把题目传上来,要不然自己去化简,或者可以代掉一个字母,根据n分之m=3分之5,用一个字母表示另一个,最后肯定可以约掉再问：已知n分之m=3分之5，求（m+b分之m）+（m-b分之m）-（m平方-n平方

m>n>0,m^2+n^2=3mn,——》(m+n)^2=m^2+n^2+2mn=5mn,——》m+n=√(5mn),(m-n)^2=m^2+n^2-2mn=mn,——》m-n=√(mn),——》(m

因为m/n=5/3所以可设m=5k,n=3k所以m/(m+n)+m/(m-n)-n^2/(m^2-n^2)=m(m-n)/(m^2-n^2)+m(m+n)/(m^2-n^2)-n^2/(m^2-n^2

3m（m－n）－2n（m－n）²＝（m－n）（3m－2mn＋2n²）