= = = & gt(3-m- 1)x^2+(-k-3+ 1)xy+(4+3-n)y^2=0

= = = & gt(2-m)x^2+(-k-2)xy+(7-n)y^2=0

The above formula applies to any x and y.

So: 2-m = 0; -k-2 = 0； 7-n=0

So, m=2, k=-2, n=7.