Question

Write a function rule for the values in the table

10
10
12
20
18
50
20
60
y=

Answer 1

y = 5x - 40

Explanation:

The function rule can be written in slope-intercept form, y = mx + b.

Let's find slope (m) and y-intercept (b) of the function, using the values given in the table.

✔️Slope (m) = change in y / change in x

Using two pair of values from the table, (10, 10) and (12, 20),

Slope (m) = (20 - 10) / (12 - 10) = 10/2 = 5

Slope (m) = 5

✔️ y-intercept (b):

Substitute (x, y) = (10, 10) and m = 5 into y = mx + b.

Thus:

10 = 5(10) + b

10 = 50 + b

10 - 50 = b

b = -40

✔️Write the function by substituting m = 5 and b = -40 into y = mx + b

Thus:

y = 5x + (-40)

y = 5x - 40