Question

How do you combine `(z+7) - (4-z)`?

Answer 1

You can get rid of the brackets but remember that the minus sign changes all the signs inside the second bracket:
`(z+7)-(4-z)=`
`=z+7-4+z=`
Now add (algebraically, i.e., considering the signs) similar terms (`z` with `z` and numbers with numbers):
`=2z+3`