Re-arrange (3x+y)/2 = x+z making x the subject.

To make x the subject we want to try to get all the x's on one side of the equals sign! Firstly to get rid of the fraction we multiply both sides by 2, giving 3x+y= 2(x+z). We then expand the brackets on the right hand side giving us 3x+y=2x+2z. Then we collect terms and bring the x's to one side, in this case I will bring the x's to the left hand side, and therefore minus 2x from both sides, giving 3x+y-2x=2z. In order to only have x's on the left hand side, we minus y from both sides (remember what you do to one side you do to the other!). Therefore resulting in, 3x-2x=2z-y which can be simplified to  x=2z-y