已知m^2+9n^2+6m+6n+10=0,求(m^2-6mn+9n^2)/(m-3n)-(4m^2-9n^2)/(2m-3n)

问题描述:

已知m^2+9n^2+6m+6n+10=0,求(m^2-6mn+9n^2)/(m-3n)-(4m^2-9n^2)/(2m-3n)

m^2+9n^2+6m+6n+10=0
m^2+6m+9+9n^2+6n+1=0
(m+3)^2+(3n+1)^2=0
m=-3 n=-1/3
后边自己求

已知可化为:(m+3)²+(3n+1)²=0
即有:m=-3,n=-1/3
原式=[(m-3n)²/(m-3n)]-[(2m-3n)(2m+3m)/(2m-3n)]
=(m-3n)-(2m+3n)
=-m-6n=3+2=5

m^2+9n^2+6m+6n+10=0
(m+3)²+(3n+1)²=0
所以:m+3=0;3n+1=0
解得:m=-3;n=-1/3
(m^2-6mn+9n^2)/(m-3n)-(4m^2-9n^2)/(2m-3n)
=(m-3n)²/(m-3n)-(2m+3n)(2m-3n)/(2m-3n)
=m-3n-3m-3n
=-2m-6n
=6+2
=8

m^2+9n^2+6m+6n+10=(m+3)^2+(3n+1)^1=0
得 m=-3, n=-1/3
(m^2-6mn+9n^2)/(m-3n)-(4m^2-9n^2)/(2m-3n)
=(m-3n)^2/(m-3n)-(2m-3n)(2m+3n)/(2m-3n)
=(m-3n)-(2m+3n)=-m-6n=3+2=5

m^2+9n^2+6m+6n+10=0m^2+6m+9+9n^2+6n+1=0(m+3)^2+(3n+1)^2=0(m+3)^2=0,(3n+1)^2=0m=-3n=-1/3(m^2-6mn+9n^2)/(m-3n)-(4m^2-9n^2)/(2m-3n)=(m-3n)^2/(m-3n)-(2m-3n)(2m+3n)/(2m-3n)=m-3n-(2m+3n)=m-3n-2m-3n=-m-6n=-(...

条件得(m+3)^2+(3n+1)^2=0
m=-3,n=-1/3
代入=5