Answer
$\text{a)
a solution
}\\\text{b)
NOT a solution
}\\\text{c)
a solution
}$
Work Step by Step
$\bf{\text{Solution Outline:}}$
Use the position of the number on the number line to evaluate if it satisfies the given inequality, $
y\le19
.$
$\bf{\text{Solution Details:}}$
The inequality $
y\le19
$ is satisfied by all numbers that appear on/on the left of $19$ in the number line.
a) In the number line, $
18.99
$ appears on the $\text{
left
}$ of $
19
.$ Hence, it is $\text{
a solution
.}$
b) In the number line, $
19.01
$ appears on the $\text{
right
}$ of $
19
.$ Hence, it is $\text{
NOT a solution
.}$
C) In the number line, $
19
$ appears $\text{
exactly on
}$ $
19
.$ Hence, it is $\text{
a solution
.}$
Therefore,
\begin{array}{l}\require{cancel}
\text{a)
a solution
}\\\text{b)
NOT a solution
}\\\text{c)
a solution
}
\end{array}