z=-3
Explanation
[tex]42=-7(z-3)[/tex]
Step 1
divide both sides by -7
[tex]\begin{gathered} 42=-7(z-3) \\ \frac{42}{-7}=\frac{-7(z-3)}{-7} \\ -6=(z-3) \\ -6=z-3 \end{gathered}[/tex]Step 2
add 3 in both sides
[tex]\begin{gathered} -6=z-3 \\ -6+3=z-3+3 \\ -3=z \\ \end{gathered}[/tex]so,the answer is
z=-3
