2mn∕4m²-9 与2m-3∕2m 3 通分
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(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,
再答:错了再答:后面是3(m-n)再答:是15+12=27再问:谢谢了
因为|m-n-2|大于等于0(mn-1)的2次方大于等于0且|m-n-2|与(mn-1)的2次方互为相反数所以m-n-2=0mn-1=0则m-n=2mn=1(-2mn+2m+3n)-(3mn+2n-2
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
3(m^2+mn)-4(mn-2m^2n)+mn=3m²+3mn-4mn+2m²n+mn=3m²+2m²n=m²(3+2n)
“liljw0924”:二个数的分母分别为4m²-9和2m+34m²-9=(2m)²-3²=(2m+3)×(2m-3)它们的公分母是(2m+3)×(2m-3)通
|m-n-2|=-(mn-1)²;所以m-n-2=0;m=n+2;mn-1=0;原式=(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=-2mn+2m+3n-3mn-2n
先合并同类项,得3(m-n)-6mn+9,代入已知数据,有结果27
4m²-9=(2m+3)(2m-3)所以最简公分母就是4m²-9所以(2m-3)/(2m+3)=(2m-3)²/(4m²-9)
(-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)=-
(9-2mn+2m+3n)-(m+4n+mn)=9-2mn+2m+3m-m-4n-mn=9-mn+(m-n)=9-(-1)+4=14
-2mn+2m+3n-3mn-2n+2m-4n-m-mn=-6mn+3m-3n=-6mn+3(m-n)=6+9=15
2mn/(4m^2-9)(2m-3)/(2m+3)分子分母同时乘(2m-3)=(2m-3)(2m-3)/(2m+3)(2m-3)=(4m^2-12m+9)/(4m^-9)
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
3/(2M-N)=3(2M-N)/(2M-N)²2MN/(4M²-4MN+N²)=2MN/(2M-N)²如果不懂,请Hi我,祝学习愉快!
最简公分母是2(x+y)²x-y/2x+2y=(x+y)(x-y)/2(x+y)².xy/(x+y)^2=2xy/2(x+y)².最简公分母是(m+3)(2m-3)2mn
①2mn/4m^2-9=2mn/[(2m+3)(2m-3)]②2m-3/2m+3=(2m-3)(2m-3)/[(2m+3)(2m-3)]=(2m-3)²/[(2m+3)(2m-3)]③2mn
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
3(m^2n+mn)-4(mn-2m^2n)+mn.=3m^2n+3mn-4mn+8m^2n+mn.=11m^2n.
(-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