If you have a system of linear equations and you want to know the solution to both of them graph them out. The intersection (if there is any) will be the solution to both of them.
There’s three things you need to know to do this:
1). How to read a line formula y=mx+b (What’s the slope (m)? What’s the Y-intercept (b))
2). How to plot the Y-intercept on graph.
3). How to extent the line from the slope (m)
When you plotted both lines, the point where the two lines meet has coordinates (x, y). If you “Plug” those coordinates into your line equations, they will have the same y-value.