C. c. what is the slope of (2,5) and (-1,2)

Greetings from Brasil...

The slope is given by the expression:

ΔY/ΔX

where

ΔY = Y₂ - Y₁

ΔX = X₂ - X₁

slope = ΔY/ΔX

slope = (Y₂ - Y₁)/(X₂ - X₁)

slope = (2 - 5)/(- 1 - 2)

slope = (- 3)/(- 3)

answer: all of the odd numbers were opened

the first person was the one that was opening all of the lockers. since one is odd, this causes all of the odd number lockers to be opened in the end.