Question

Which function is described by values in the table?

x y
1 8
3 6
5 4
7 2

a) y= -2x + 10
b) y= -2x + 9
c) y= -x + 9
d) y= -x + 10

Answer 1

Answer: The correct equation (representing the data values in the table) is y = -x + 9.

Answer 2

One way to approach this problem is to go ahead and find the actual equation in slope-intercept form.

The slope of the line thru (3,6) and (5,4) is m = (6-4) / (3-5), or -2/2, or -1.

Subbing the known values of m, x and y, we get:

4 = -(5) + b. Then b = 9.

The correct equation (representing the data values in the table) is y = -x + 9.