ok. first you have to pick x or y or whatever variable you have and the number multiplied with it has to be the same in each equation but one has to be positive and one negative.
lets pick x
y=-2x+6
3y=x-3/ *2
so the x are positive and negative we have to multiply the equation with 2
y=-2x+6
6y=2x-6
now you have to add the equations. you do that by adding each side of the equatins together like this:
y+6y=-2x+6+2x-6 the x will cancel out
7y=0
y=0
now just go back to one of the previous equations and put the y in it.
0=-2x+6
2x=6
x=3
here you go
