The slope of this line is:
3-(-6)
m = ------------ = 1
3-(-3)
and so, using the point-slope formula for the equation of a str. line,
y-3 = 1(x-3), or y-3 = x - 3, or 1x - 3 - y + 3 = 0. Then 1x - 1y = 0 (in standard form). Alternatively, y = x (slope-intercept form).
