已知m^2+9n^2+4m-6n+5=0,求m,n的值
当m,n取第(1)小题的值时,求(2m-3n)^2-(2m+3n)(2m-3n)+(2m+3n)^2的值。...
当m,n取第(1)小题的值时,求(2m-3n)^2-(2m+3n)(2m-3n)+(2m+3n)^2的值。
展开
1个回答
展开全部
m^2+9n^2+4m-6n+5=0,
m^2+4m+4+9n^2-6n+1=0,
(m+2)²+(3n-1)²=0,
(m+2)²>=0,(3n-1)²>=0,
所以(m+2)²=0,m=-2;(3n-1)²=0,n=1/3;
(2m-3n)^2-(2m+3n)(2m-3n)+(2m+3n)^2
=[(2m-3n)-(2m+3n)]²+(2m+3n)(2m-3n)
=[2m-3n-2m-3n)]²+(2m)²-(3n)²
=[-6n)]²+(2m)²-(3n)²
=[-6/3)]²+(-4)²-(1)²
=4+16-1
=19
或
(2m-3n)^2-(2m+3n)(2m-3n)+(2m+3n)^2
=(-4-1)^2-(-4+1)(-4-1)+(-4+1)^2
=25-15+9
=19
m^2+4m+4+9n^2-6n+1=0,
(m+2)²+(3n-1)²=0,
(m+2)²>=0,(3n-1)²>=0,
所以(m+2)²=0,m=-2;(3n-1)²=0,n=1/3;
(2m-3n)^2-(2m+3n)(2m-3n)+(2m+3n)^2
=[(2m-3n)-(2m+3n)]²+(2m+3n)(2m-3n)
=[2m-3n-2m-3n)]²+(2m)²-(3n)²
=[-6n)]²+(2m)²-(3n)²
=[-6/3)]²+(-4)²-(1)²
=4+16-1
=19
或
(2m-3n)^2-(2m+3n)(2m-3n)+(2m+3n)^2
=(-4-1)^2-(-4+1)(-4-1)+(-4+1)^2
=25-15+9
=19
推荐律师服务:
若未解决您的问题,请您详细描述您的问题,通过百度律临进行免费专业咨询