Answer
$y=2x+2$
Work Step by Step
Let $(x_1,y_1)=(1,4)$ and $(x_2,y_2)=(3,8)$.
The slope is given by $m=\dfrac{y_2-y_1}{x_2-x_1}$.
Substituting the known values we get
$\begin{align} m &=\frac{8-4}{3-1} \\&=\frac{4}{2} \\m &=2\end{align}$
The point-slope form of a line is $y-y_1=m(x-x_1)$.
Using the point $(1, 4)$ and $m=2$, we obtain:
$\begin{align} y-4 &=2(x-1) \\ y-4 &= 2x-2 \\y&=2x-2+4 \\y&=2x+2\end{align}$
The required equation of the line is $y=2x+2$
