The answer should be 13, why is it not on the choices

I know that 1+1=2 because thats baby work. I knew that [email protected] since In pre school.So that question is so easy except for 5th grade questions because I am only in 2 grade

A coefficient is a number used to multiply a variable.

So in this expression, 5 is multiplied with the variable X hence 5 is the Coefficient.

- 6 is the expression.