Given the figure, find the values of x and z.

The angle with (6x-23) and (9x-67) together make a straight line, so their sum is 180:
(6x-23) + (9x-67) = 180
So you need to solve that for x.
For z, z and (6x-23) are vertical angles, so their angle measures are the same.
z = 6x-23
[tex]\\ \sf\bull\dashrightarrow 9x-67+6x-23=180[/tex]
[tex]\\ \sf\bull\dashrightarrow 9x+6x-67-23=180[/tex]
[tex]\\ \sf\bull\dashrightarrow 15x-90=180[/tex]
[tex]\\ \sf\bull\dashrightarrow 15x=180+90=270[/tex]
[tex]\\ \sf\bull\dashrightarrow x=18[/tex]
Now
[tex]\\ \sf\bull\dashrightarrow z=6x-23[/tex]
[tex]\\ \sf\bull\dashrightarrow z=18(6)-23[/tex]
[tex]\\ \sf\bull\dashrightarrow z=108-23[/tex]
[tex]\\ \sf\bull\dashrightarrow z=85[/tex]