The distance from the point (3,4) to the line y = -x is
or approximately 4.95 units.
The formula for the distance between a point (x₀,y₀) and a line Ax + By + C = 0 is expressed as:
distance =

Given the parameter:
The equation of the line is: y = -x
x + y = 0
Hence, A = 1, B = 1 and C = 0.
Point: (3,4):
x₀ = 3 and y₀ = 4
Plug these values into the above formula and simplify:
distance =


Therefore, the distance measures approximately 4.95 units.