Identify each part of the algebraic expression as the Coefficient, Constant, or Variable
a+3b

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Two friends are reading books. jimmy reads a book with 21,356 words. his friend bob reads a book with one-and-a-half times as many words. which expression represents the number of words bob reads?

Pls never taught i’m really confused and i rlly need