So first I would say is that you can start off by subtracting 10 from both sides and then yo would be left with 3x=3x+5x-10 so we are going to combine like terms which is in this case 3x+5x which is 8x. so 3x= 8x-10 so now we can subtract 8x from both sides so 8x-8x = 0 it cancels out then we are left with -5x=-10 x=2 . Hoped that helped ! :)