It is known that M minus 1 of equation x plus 2m of equation y plus N is equal to 5, which is a quadratic equation of two variables

It is known that M minus 1 of equation x plus 2m of equation y plus N is equal to 5, which is a quadratic equation of two variables

Hello
Because it's a quadratic equation of two variables
So M-1 = 1,
2m+n=1
[guarantee one item at a time]
So m = 2
n=-3
So m + n = - 1