Question

A local public library decides to track the number of hours that a certain computer is being used. The table represents the number of hours, y, which is dependent on the number of days, x.

x
y
3
21
5
37
7
53

What is the linear equation that represents this situation?
y = 8 x + 45
y = 8 x minus 3
y = 2 x + 16
y = 2 x minus 32

Answer 1

Find the slope: between x=3 and x=5, y goes from 21 to 37, change = 16 over 2 days → slope = 8.
Use y = 8x + b and plug (3,21): 21 = 8·3 + b → b = 21 − 24 = −3.
So y = 8x − 3.