parallel lines have the same slope so we need to find the slope of the line
2x-3y=9 get y alone
-3y=-2x+9 subtract 2x
y=2/3 x -3 divide by -3
the slope of the line is 2/3
the point slope form of the equation is
(y-y1) = m(x-x1) where m is the slope and (x1.y1) is the point
y-3 = (2/3) * (x+6) distribute the 2/3
y-3 = 2/3 x + 4 add 3 to both sides
y = 2/3 x +7