Each day, Talisa exercises by first stretching and then swimming some laps, as shown in the table. Use the table of her exercise data.

Question

Laps	5	6	7	8	9
Time (min)	25	28	29	30	32

Which could be an equation of a trend line for the data?

A. y = 12x + 15

B. y = 2x + 15

C. y = 12x + 25

D. y = 2x + 25

Answer 1

Whenever you solve for a line, often you want to think of SLOPE first.

Slope is the (Change in y/Change in x).

In this case, it is the (Change in time/Change in laps).

For each increase of 1 lap, time increases ~2 min, So slope = 2/1 = 2.

Slope is the coefficient in front of the x variable.

Cancel out the 2 equations that do NOT have a slope of 2.

Now, test out the 2 equations remaining by putting in # of laps for x to see which equation gives you the closest value for y (the time).