Help and explain please

Question

9m+n=22
m-3n=18

Answer 1

Assuming you want to solve these simultaneously.

9m + n = 22
m - 3n = 18

To eliminate variable n, mulyiply the first equation by 3

3(9m + n = 22) = 27m + 3n = 66
Now add these two equations together

27m + 3n = 66
m - 3n = 18
28m + 0 = 84
28m = 84
m = 3

Substitute m = 3 in m - 3n = 18, to find n
m = 3
m - 3n = 18
3 - 3n = 18
-3n = 15
n = -5

So, the solution is,
(3, -5)