Answer
The $y$ intercept of the line is $5$.
Work Step by Step
Consider a line that passes through the point $\left( 3,-1 \right)$ and has a slope of $-2$.
Substitute $\left( {{x}_{1}},{{y}_{1}} \right)=\left( 3,-1 \right)$ and $m=-2$ (the slope of the given line) in the equation:
$\begin{align}
& y-\left( -1 \right)=-2\left( x-3 \right) \\
& y+1=-2x+6
\end{align}$
Solve the above equation for y:
$\begin{align}
& y+1=-2x+6 \\
& y=-2x+6-1 \\
& y=-2x+5
\end{align}$
To calculate the y intercept of the line, compare the last equation with the general slope-intercept form of a line as follows:
$b=5$
Hence, the $y$ intercept of the given line is $b=5$.
