Answer:
z = -14
Step-by-step explanation:
[tex] - \frac{z}{2} + 35 = 42[/tex]
[tex] - z + 70 = 84[/tex]
[tex] - z = 84 - 70[/tex]
[tex] - z = 14[/tex]
[tex]\boxed{\green{z = - 14}}[/tex]
