What does it mean when a tool of assessment is characterized as reliable? Under what conditions might one expect an otherwise useful tool of assessment to be unreliable?

Reliability refers to whether an assessment instrument gives the same results each time it is used in the same setting with the same type of subjects. Reliability essentially means consistent or dependable results. Reliability is a part of the assessment of validity.

Not sure but hope my answer helps! :)

the answer is on the pic above

or

2*2^3 - 3*2^2 - 18*2 - 8

= - 40