Rewrite the first function so that the two functions are in standard form:
y - 3 = -2x - 8 => y = 3 - 2x - 8 => y = -2x - 5
and
y= -2x - 5
We can now see immediately that these two functions have the same slope (-2) and same y-intercept (providing that you meant "y = -2x - 5).
The graphs of these 2 functions are identical.