Question

Here’s a graph of a linear function. Write the equation that describes that function. (Zoom in if blurry)

(Express it in slope-intercept form.)

Answer 1

Answer: y = x/2 + 3

Explanation:

The equation of a straight line can be represented in the slope-intercept form, y = mx + c

Where c = intercept

Slope, m = change in value of y on the vertical axis / change in value of x on the horizontal axis

change in the value of y = y2 - y1

Change in value of x = x2 -x1

y2 = final value of y

y 1 = initial value of y

x2 = final value of x

x1 = initial value of x

Looking at the graph,

y2 = 6

y1 = 4

x2 = 6

x1 = 2

Slope,m = (6 - 4)/(6 - 2) = 2/4 = 1/2

To determine the intercept, we would substitute x = 2, y = 4 and m= 1/2 into y = mx + c. It becomes

4 = 1/2 × 2 + c

4 = 1 + c

c = 4 - 1

c = 3

The equation becomes

y = x/2 + 3