Question

How do you solve `15 - z = 6`?

Answer 1

`z = 9`
`15 - 9 = 6`

Explanation:

`15 - z = 6`

The goal of this equation is solve for the value of the variable, `z`. This is a one-step problem. To do this, we want to make `z` by itself to find its value. Because `15` is also on the same side, and we only want `z`, we'll subtract `15` to cancel out positive `15`.

Because we subtract `15` to one side, we'll have to subtract `15` from the other side. So, you're left with this:

`-z = -9`

Because you can't have a negative variable, divide by `-1` to make the equation positive. Recall that two negatives create a positive, so:

`z = 9`

Confirm that this is right by plugging it into your equation:

`15 - z = 6`
`15 - 9 = 6`
`6 = 6`

This is correct.