3m-2n=1 2m 3n=5-搜答案-搜狗做题网

应该是10吧

5m+3n=8 5m-3n=2,求m+n

5m+3n=85m-3n=2两式子相加得10m=10∴m=15m+3n=85+3n=8n=1m+n=1+1=2

此题先通分,通过计算可得m^2+m^2-n^2/m^2-n^2=1+m^2/m^2-n^2=1+25/16=41/16

既然是相反数,就是m和n两者加起来为0的,例如-1和1,-2和2就互为相反数,所以这里答案是0咯

m/(m+n)+m/(m-n)-n^2/(m^2-n^2)=m(m-n)/(m+n)(m-n)+m(m+n)/(m-n)(m+n)-n^2/(m^2-n^2)=（m(m-n)+m(m+n)）/(m^2

已知﹣3xy的n＋1次方与5x的m＋3y四次方是同类项则1=m+3n+1=4解得m=-2n=3所以3n四次方-6m3n-4n四次方＋2nm3次方=-n^4-4m^3n=-3^4-4*(-2)^3*3=

3m+2n=7 3m-n=5m=?n=?

3m+2n=7（1）3m-n=5（2）（1）-（2）得：2n+n=7-5=2；n=2/3;带入（1）得：3m+4/3=7;3m=17/3;m=17/9;如果本题有什么不明白可以追问,

原式=mn（m2-9）=mn（m+3）（m-3）．故答案为：mn（m+3）（m-3）

m-{n-2m+[3m-(6m+3n)+5n]}=m-n+2m-[3m-(6m+3n)+5n]=3m-n-3m+(6m+3n)-5n=-6n+6m+3n=6m-3n

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

"m/(m+n)+m/(m-n)-n^2/(m^2-n^2)=(m/n)/(1+m/n)+(m/n)/(-1+m/n)-1/((m/n)^2-1)=(5/3)/(1+5/3)+(5/3)/(5/3-1

[(3m+2n)(3m-2n)-(m+2n)(5m-2n)]÷(1/3)m=[9m²-4n²-5m²+2mn-10mn+4n²]÷(1/3)m=[4m²

答：(5m+3n)^2-(m-3n)(25m-3n),其中m=1,n=2=25m²+30mn+9n²-(25m²-3mn-75mn+9n²)=30mn+78mn

等于0

m/(m+n)+n/(m-n)-n^2/(m^2-n^2)=[m(m-n)+n(m+n)-n^2]/(m^2-n^2)=m^2/(m^2-n^2)=1/(1-(n/m)^2)=1/(1-(3/2)^2

已知m=5n,则原式=(5n/(5n+n))+(5n/(5n-n))-(n^2)/(((5n)^3)-n^2)=(5/6)+(5/4)-[1/(125n-1)]=(25/12)-[1/(125n-1)

(2m-n)/(m+2n)=5∴(m+2n)/(2m-n)=1/5∴3(2m-n）/m+2n-m+2n/2m-n+3=3×(2m-n)/(m+2n)+(m+2n)/(2m-n)+3=15+1/5+3=

(2m-n)/(m+2n)=5∴(m+2n)/(2m-n)=1/5∴3(2m-n）/m+2n-m+2n/2m-n+3=3×(2m-n)/(m+2n)+(m+2n)/(2m-n)+3=15+1/5+3=

2m+n分之m-2n=3所以原式=(3+1/3-5/4)[2m+n分之m-2n=3]=25/12×3=25/4