I propose a new way of solving an equation with two variablesi. Instead of simple trial and error, you can rearrange the equation and use principles of simultaneous equations in one equation. So, look at the following example.
15X= 2Y+ X
2Y= 14X
Y= 7X
15X= 14X + X
X=1
15=2Y+1
Y=7
Finally, if you have two variales and a number, there’s a neat way I discovered to solve the issue.