The points ( − 1.9 , 2.7 ) and ( 3.1 , 10.2 ) are on the graph of a linear relationship between two variables, x and y .

Question

The points (−1.9,2.7) and (3.1,10.2) are on the graph of a linear relationship between two variables, x and y.



1) What is the constant rate of change of y with respect to x?

2)Write a formula that expresses y in terms of x.

3)What is the value of y when x=115?

Answer 1

rate of change = slope = (10.2 - 2.7) / (3.1 - (-1.9)) = 7.5 / 5 = 1.5

y - 10.2 = 1.5(x - 3.1)

Solve for y and plug in 115 for x.