Write the phase as an algebraic expression

Eleven times a number

Eleven times a number? Sounds like multiplication problem.

11 * ?

But multiply by what? We don't know. It just says 'a number'. In algebra, we use variables to represent a number.

11 * x

Or you could do 11x. In algebra, it means the same thing.

the algebraic equation of eleven times a number is 11x