Answer:
You can use substitution, elimination, or graphing.
Explanation:
So what I would do, is using elimination because you have two variables that are the same, what I mean is that you have two -3y's, So, take one equation, lets do the top one, and multiple the whole thing, yes, the WHOLE THING meaning both sides by -1. This will give you -6x+3y= -12. The negative turns to positive because you multiply the -3y by -1. Notice how you have a +3y in the top equation now and a -3y in the bottom one. This is why the method is called elimination, you can cross out the +3y and -3y and combine both equations. You now have -2x=12. Divide both sides by -2, x=-6. Plug -6 in the first equation, you get 6(-6)-3y=12 which goes to -36-3y=12. Add 36 on both sides, you get -3y=48. Divide both sides by -3, you get y=-16. Oh yeh, plug y into one of the equations and solve for x, i forgot to say that.