Answer: z = 3
Step-by-step explanation: To solve this equation for z, we can first combine our like terms on the left side of the equation. Since 12 and 7 both have z after their coefficient, we can subtract 12z - 7z to get 5z.
Now we have 5z - 2 = 13.
To solve from here, we add 2 to the left side of the equation in order to isolate 5z. If we add 2 to the left side, we must also add 2 to the right side. On the left side, the -2 and +2 cancel out. On the right, 13 + 2 simplifies to 15.
Now we have 5z = 15.
Solving from here, we divide both sides of the equation by 5 to get z alone. On the left side, the 5's cancel out and we are simply left with z. On the right side, 15 divided by 5 simplifies to 3 so we have z = 3.