[tex]\huge\boxed{x-2y=-6}[/tex]
Hey there! We can solve this problem by setting up the equation in slope-intercept form and changing it into standard form.
(I'm assuming that the problem meant the slope is [tex]\frac{1}{2}[/tex].)
[tex]\begin{aligned}y&=mx+b&&\smash{\Big|}&&\text{Start with slope-intercept form.}\\y&=\frac{1}{2}x+3&&\smash{\Big|}&&\text{Substitute in the known values.}\\-\frac{1}{2}x+y&=3&&\smash{\Big|}&&\text{Move the variables to the left.}\\x-2y&=-6&&\smash{\Big|}&&\text{Multiply everything by $-2$.}\end{aligned}[/tex]
