Answer:
The values of y such that the barn is 70 yards from the well are y=76 or y=-64
Explanation:
Distance in the Plane
Given two points in a rectangular system of coordinates (a,b) and (c,d) the distance measured between them is calculated with the formula

The barn is located at (4,6) and the well is located at (4,y). The value of y must be calculated in such a way the distance between the barn and the well is 70 yards. Thus, the equation to solve is

Operating

When taking the square root we must be careful for it has two signs:

Rearranging

which yields to these solutions


And also


The values of y such that the barn is 70 yards from the well are y=76 yards or y=-64 yards