first you have to combine the like terms of z and 2z on the left side. Then you must distribute the 0.25 to 8z and -4. So then your equation should look like this:
2z - 1 = 8 - 1z
So now you add 1z to both sides. The 1z on the right cancels out and now you have 3z - 1 = 8
Next you add 1 to both sides and it cancels out on the left: 3z = 9
Then you just divide by 3 on both sides to get the variable by itself. The 3 on the left cancels out and 9 divided by 3 equals 3! So z = 3
