.
Use the general formula:
the distance from the point (p,q) to a straight line ax + by + c = 0 is
d =
.
Regarding this formula, see the lesson The distance from a point to a straight line in a coordinate plane in this site.
In your case, the equation of the straight line is 2x + y - 3 = 0, so the distance is
d =
=
=
~ 1.897367 (approximately).