Answer
a) See graph;\\
b) See graph; $-\dfrac{5}{7}\lt -\dfrac{9}{25} $
Work Step by Step
a) Plot the number $-\dfrac{9}{25}$ on the real number line.
b) Plot the number $-\dfrac{5}{7}$ on the number line.
Then plot both numbers on the same number line. As $-\dfrac{5}{7}$ is to the left of $-\dfrac{9}{25}$, $-\dfrac{5}{7}$ is smaller than $-\dfrac{9}{25}$.
$-\dfrac{5}{7}\lt -\dfrac{9}{25} $