Question

若m×m+n×n-6n+4m+13=0,则m×m-n×n=?

Answer 1

由m×m+n×n-6n+4m+13=0 得

(m×m+4m+4)+(n×n-6n+9)=0 得

(m+2)^2+(n-3)^2=0 得

m=-2

n=3

所以 m^2-n^2=4-9=-5