i don't understand how to do these
1+3x-x=x-4+2z
3+3x-(x-2)=3x+4
You posted this twice. I was hoping you'd do the second one yourself, after seeing how I did the first one.
When you combine similar terms on the left side of
3+3x-(x-2)=3x+4
you get
2x + 5 = 3x + 4
For the next step, subtract 2x from both sides of the equation.
5 = x + 4
From there, you should be able to solve for x in one more step.