Solution:
Given:
A number line.
To get the expression that is positive, we estimate the values of the points on the number line.
[tex]\begin{gathered} Assume\text{ }a\approx-1.8 \\ \\ Hence, \\ -a-1=-(-1.8)-1 \\ =1.8-1 \\ =0.8 \\ \\ This\text{ gives a positive result} \end{gathered}[/tex]
Also, for the other expression,
[tex]\begin{gathered} Assume\text{ }b\approx2.5 \\ \\ Hence, \\ -b+2=-2.5+2 \\ =-0.5 \\ \\ This\text{ gives a negative result} \end{gathered}[/tex]
Therefore, the expression that is positive is -a -1
OPTION A is correct.
