the numbers with NO zeros should be first and the first number should be turned to a whole so like "2.4". Since there are 3 zeros (including the zero in the whole number place) you would write the 3 as the number in the right corner. And there is a minus sign beside the 3 because the Zeros are first. :)
Alright, so we start off my subtracting 4a from both sides, separating the x and getting 10-4a=2x. Next, we divide both sides by 2, getting that 5-2a=X
