m^2+2mn=384,3mn+2n^2=560,则2m^2+13mn+6n^2-438的值是
问题描述：
m^2+2mn=384,3mn+2n^2=560,则2m^2+13mn+6n^2-438的值是
答
m^2+2mn=384,3mn+2n^2=560
2m²+4mn=768 9mn+6n²=1680
2m²+4mn+9mn+6n²=768+1680
2m²+13mn+6n²=2448
∴2m²+13mn+6n²-438=2448-438=2010