Vectors are different kinds of mathematical entities from scalars. Notationally, we distinguish vectors from scalars by putting an arrow over the letter denoting a vector quantity and using no arrow for a scalar quantity. In MAP, vectors will in addition be highlighted by letters in boldface. Consider the following three equations:

(1) + b = (2) + = c (3) a + 4 = .

Which ones of these equations make mathematical sense?

(a) all of them (b) none of them

(c) equation (1) only (d) equation (2) only (e) equation (3) only