So the easiest way to solve is to use substitution method. This is what you do.
y = 3x - 4 -3y = -9x + 12 (Substitute the y-value in the second equation with the first equation.) -3(3x - 4) = -9x + 12 Distribute. -9x + 12 = -9x + 12 Subtract 12 from both sides. -9x = -9x + 0 Add 9x to both sides. 0 = 0 Both numbers are equal so it is infinate solution as the answer. I hope this helps love! :)