First let's determine the slope
y2 - y1 2-5 -3
------- = ----- = --- = 1
x2 - x1 -3-0 -3
Now the point slope equation of a line looks like
y-y1 = m(x-x1), where m = slope calculated above.
y-5 = 1(x-0)
Distributing and rearranging terms
y-5 = x, or
y = x + 5