For the g=6x you would have to divide the 6 from both sides so it would end up being x=g/6. For Z=m-x you can add the x to both sides making it z+x=m and then subtracting the z from both sides making it x=m-z. Then for u=2x-2 you would have to add 2 to both sides making it u+2=2x and then divide 2 from both sides making it x= 2+u/2.