9514 1404 393
Answer:
(3/2)√2 ≈ 2.1213 units
Explanation:
The distance d from point (x, y) to line ax+by+c = 0 is given by ...
d = |ax +by +c|/√(a^2 +b^2)
We can write the equation of the line as ...
x + y -4 = 0
so the distance is ...
d = |x + y - 4|/√(1^2 +1^2)
For point (x, y) = (2, -1), the distance is ...
d = |2 +(-1) -4|/√2 = 3/√2 = (3√2)/2
The distance from A(2, -1) to the line y = -x +4 is (3√2)/2 units.