Multiply the 5 to the 7 and 3x--> 35 + 15x -12. Then add 12 to the -12, making it 0 (inverse operations), and add 12 to the 35 making it 47 + 15x. :) Then you would simply divide the 15 by 15x (making the variable by itself). your answer for x should be 47/15. :> If I helped, please mark brainliest!!