Question

What does it mean when there is no coefficient of the variable

Answer 1

Any variable always has a coefficient, just if the coefficient is 1 we don't right it. So if the variable doesn't have any coefficient written, the coefficient is 1. For example, the $x^2$ term in the following polynomial has a coefficient of 1:

$x^2 + 2x + 1$

Even though there isn't a 1 in front of the $x^2$, the coefficient is 1.