Answer
$m=-1$
Work Step by Step
Using $m=\dfrac{y_1-y_2}{x_1-x_2}$ or the Slope Formula, then the slope of the line containing the given points, $(
0,7
) \text{ and } (
-3,10
)$, is
\begin{array}{l}
m=\dfrac{7-10}{0-(-3)}
\\\\
m=\dfrac{7-10}{0+3}
\\\\
m=\dfrac{-3}{3}
\\\\
m=-1
.\end{array}