#### Answer

$\sqrt{17} \text{ units}$

#### Work Step by Step

$\bf{\text{Solution Outline:}}$
Use the Distance Formula to find the distance between the given points $\left(
3,7
\right)$ and $\left(
-1,8
\right)$.
$\bf{\text{Solution Details:}}$
With the given points, then $x_1=
3
,$ $x_2=
-1
,$ $y_1=
7
,$ and $y_2=
8
.$ Using the Distance Formula which is given by $d=\sqrt{(x_1-x_2)^2+(y_1-y_2)^2}
,$ then
\begin{array}{l}\require{cancel}
d=\sqrt{(3-(-1))^2+(7-8)^2}
\\\\
d=\sqrt{(3+1)^2+(7-8)^2}
\\\\
d=\sqrt{16+1}
\\\\
d=\sqrt{17}
.\end{array}
Hence, the distance is $
\sqrt{17} \text{ units}
.$