There are two ways to do this but the way I prefer is to make one of the equations in terms of one variable and then 'plug this in' to the second equation. I will demonstrate
Look at equation 1, this can quite easily be manipulated to show .
Then because there is a y in the second equation (and both equations are simultaneous) we can 'plug in' our new equation where y is in the second one which can then be solved for x since there is only one variable and then with our x solution we can work out our y solution by using the equation we manipulated .
So the solution to these equations is x=-2 when y=6
If ken saved $120 dollars and didn’t spend any of it, he would still have $120. (I don’t exactly know if the problems came up because all I can see is your question)