i did it pretty quickly so it might be wrong, but is the answer x = 12, and y = 20?
if so, for the first equation i multiplied each side by 12, so i got 3y-4x=12, and then multiplied each side on the second equation by 10, so i got 2y + 5x = 100. multiply 3y-4x=12 by 5 and 2y+5x=60 by 4, then add --> you should get 23y = 460 --> y = 20, then solve for x