Answer
a. 9
b. 8
c. 0
Work Step by Step
a. the absolute value of $-9$ is 9 because its distance from 0 on the number line is 9.
b. The absolute value of $8$ is 8 because it is 8 units from the number line.
c. It looks like a trick question, but the absolute value of 0 is 0 because 0 is well, 0 units from itself (0) on the number line. So the answer is 0.