4M2-9分之2mn与2m n分之2m-3同分
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![4M2-9分之2mn与2m n分之2m-3同分](/uploads/image/f/325529-17-9.jpg?t=4M2-9%E5%88%86%E4%B9%8B2mn%E4%B8%8E2m+n%E5%88%86%E4%B9%8B2m-3%E5%90%8C%E5%88%86)
(2m2+3n2-mn)-(3m2+4n2-mn)=2m2+3n2-mn)-3m2-4n2+mn=-m2-n2=-(m2+n2);把m2+n2=5代入上式,得上式=-5,即代数式(2m2+3n2-mn
m(m-3)-(m^2-3n)=9m^2-3m-m^2+3n=9-3m+3n=9-m+n=3m-n=-3(m^2+n^2)/2-mn=(m^2+n^2-2mn)/2=(m-n)^2/2=(-3)^2/
将两式相加可得M2-N2=2,两式相减M2-2MN+N2=14
因为m2-mn=12,mn-n2=-15,1.两式相加得m2-n2=12+(-15)=-32.两式相减得m2-mn-(mn-n2)=12-(-15),m2-2mn+n2=12+15即m2-2mn+n2
解题思路:将原代数式经过去括号后合并同类项,化简后代入数值计算即可。解题过程:
∵m2-mn=20①,mn-n2=-8②,∴①+②得:m2-n2=12,即m2-n2+2=14;①-②得:m2-2mn+n2=28.
2(mn-3m2)+[m2-5(mn-m2)+2mn]=2mn-6m2+[m2-5mn+5m2+2mn]=2mn-6m2+m2-5mn+5m2+2mn=-mn,当m=1,n=-2时,原式=-1×(-2
/>m²+n²=4mnm²-2mn+n²=6mn(m-n)²=6mn因m>n>0,则m-n=√(6mn)m²+n²=4mnm
M2-N2=(M2-MN)+(MN-N2)=20+(-12)=8M2-2MN+N2=(M2-MN)-(MN-N2)=20-(-12)=32
m2+2mn=384(1)3mn+2m2=560(2)(1)×2+(2)×32m2+4mn+9mn+13mn+6n2=384×2+560×32m2+13mn+6n2-438=2448-438=2010
已知m2-mn=21.mn-n2=-15两式相减得:m2-2mn+n2=36再问:m后面是2次方。n后面也是2次方再答:是的已知m^2-mn=21.mn-n^2=-15两式相减得:m^2-2mn+n^
原式=(m^2+n^2-2mn)/2=(m-n)^2/2=(-2)^2/2=4/2=2如果你对我的回答满意,请【采纳为满意答案】,可继续询问,直至弄懂
(2m-n)分之m
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)
不是m2;-2mn+n2;么?m2;-2mn+n2;=m2;-mn-(mn-n2)=21-(-12)=33再问:代数式m²-2mn-n²的值是多少?再答:m^2-mn=m*(m-n
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!
1-m2-n2+2mn,=1-m2-n2+2mn,=1-(m2+n2-2mn),=1-(m-n)2,=(1-m+n)(1+m-n).
方法一:根据题意,m2-mn=2,mn-n2=5,故有m2=2+mn,n2=mn-5,∴原式=3(2+mm)+2mn-5(mn-5)=31.故应填31.方法二:根据已知条件m2-mn=2,mn-n2=
∵m2-mn=7,mn-n2=-2,∴m2-n2=(m2-mn)+(mn-n2)=7+2=9;m2-2mn+n2=(m2-mn)-(mn-n2)=7-2=5.
∵m^2-mn=21、mn-n^2=15,∴两式相减,得:m^2-2mn+n^2=21-15=6.