Look at the highlighted angles in the diagram. Find m angle 1 + m angle 2 + m angle 3.

Ithink it's the first one ( let me know if it right)

You move the constant to the right side and change its sign to be 9z= -6 -8. that’s the first step.the second step would be calculate the difference of -8-6 to get -14. you equation should now be 9z=-14the last step is to divide both sides by 9 to get z=-14/9hope this