this I learn how to use elimination

step 1 – add the two equations and you will have 5y = 20, than you divide 5y = 20 by 5 and you will get y = 4

step 2 – choose any of the two equations and place the y-intercept, I chosen the equation -3x + 3y = 3  and placed the y-intercept which is 4, than I had -3x +3(4) = 3 and -3x + 12 = 3 is your answer, after that  you create zero pars with the 12, than you will have -3x = -9 and you divide both by -3 and you will get x = 3

step 3 – (3,4) is the point that both line crosses