Answer: 2z-15
Explanation
Based on the visual image, AD is a line where a point O intersects somewhere on the line. AD is represented as 3z-11, while the segment from AO is represented as z+4.
In order to find the answer, we must subtract the entire line (AD) from AO in order to find the missing segment OD.
AD - AO = OD
(3z-11) - (z+4) = OD
Distribute the negative sign so it becomes:
(3z-11) -z - 4 = OD
Now combine like terms.
(3z-z) +(- 11 -4)= OD
2z - 15 = OD
And that is your answer!