Answer
$2x-y=-2$
Work Step by Step
Using $y-y_1=m(x-x_1)$ or the Point-Slope Form of linear equations, the equation of the line with the given conditions,
\begin{array}{l}\require{cancel}
y_1=6
,\\x_1=2
,\\m=2
,\end{array}
is
\begin{array}{l}\require{cancel}
y-6=2(x-2)
\end{array}
In the form $Ax+By=C$ or the Standard Form of Linear Equations, the equation above is equivalent to
\begin{align*}
y-6&=2x-4
\\
-2x+y&=-4+6
\\
-2x+y&=2
\\
-1(-2x+y)&=(2)(-1)
\\
2x-y&=-2
.\end{align*}