Math - Algebraic Expression

Question

Translate each of the following phrases into an algebraic expression. Use the variable * to represent each unknown.

a) quadruple a number

b) eight less than double a number

c) nine more than a number is twenty

Answer 1

I'm not sure why the problem says "Use the variable * to represent each unknown." There are no unknowns in parts (a) and (b), and using * as a variable is very strange! Here's the best I can do.

a) 4 x n

b) (2 x n) - 8

c) * + 9 = 20