The second one is already in slope-intercept form.
We need to do a little work on the first one.
3x - 3y = -6
Subtract 3x from each side:
-3y = -3x - 6
Divide each side by -3 :
y = x + 2
That's the first equation. But when you unravel it like this, you find that
it's exactly the same as the second equation. Both of them represent
the same straight line on a graph. If you graphed both of them, you'd
only see one line !
The 'solution' of a pair of equations is the point on a graph where their
lines cross. There's no such point here, because each and every point
of the first equation is also a point of the second one.
This pair (system) of equations has no solution.