What is the distance from the origin to the point on the line y=2x+5 that is closest to the origin?

1 Answer
Apr 25, 2018

5

Explanation:

Our line is

y=2x+5

We get the perpendiculars by swapping coefficients on x and y, negating one of them. We're interested in the perpendicular through the origin, which has no constant.

2y=x

These meet when y=2(2y)+5=4y+5 or 5y=5 or y=1 so x=2. (2.1) is the closest point, 22+1=5 from the origin.