Question

The points (1, r) and (5, 1) lie on a line with slope 2. Find the missing coordinate r.

Answer 1

r=-7

See explanation below

Explanation:

slope= y2-y1/x2-x1

1-r/5-1=2

1-r/4=2. (simplify)

1-r=8 (cross multiply)

-r=7

r=-7