1) Covert both equations into a similar form. (In order to add equations, they need to be in the same form)
Since the first equation is written in a solvable form we need to convert the second one.
y=-4x-3
+3 +3
y+3=-4x or -4x = y+3
2) Prepare to add both equations.
-4x = y + 3
+ -4x = y + 3
The goal of this method is to eliminate one of the variables. In order to eliminate ( for instance ) the "x" we need the x's to add to 0.
In order to do that, we need to multiply one of the equations by a negative one.
y - 4x = 3 y - 4x = 3
-1 (y - 4x = 3 ) - y +4x = -3
3) Add.
y - 4x = 3
-y +4x = -3
_________
0= 0
Since both sides equal each other, there are infinitely many solutions,
Hope this helped :)