First you had subtract by ten from both sides of equation form.
[tex]10+z-10=x-10[/tex]
Then simplify by equation.
[tex]z=x-10[/tex]
Final answer: [tex]\boxed{z=x-10}[/tex]
Hope this helps!
And thank you for posting your question at here on brainly, and have a great day.
-Charlie