Question 983706
Point-Slope is a good way to begin.

Point (p,v), and slope m:
{{{y-v=m(x-p)}}}


Your example:
{{{y-2=(-1/2)(x-3)}}}, the start.
{{{y=(-1/2)(x-3)+2}}}
{{{y=-(1/2)x+3/2+2}}}, so you probably made a sign mistake - not sure.
{{{y=-(1/2)x+3/2+4/2}}}
{{{highlight(y=-(1/2)x+7/2)}}}  or {{{highlight(y=-(1/2)x+3&1/2)}}}