The table compares the final cost of groceries after a coupon is used.
Cost Before
Coupon (a)
$20
$21
$22
$23
Cost After
Coupon (b)
$17.50
$18.50
$19.50
$20.50
Which equation models the relationship?

y = -2.5 + x

Explanation:

Given the data:

__XY

$20 __$17.50

$21 __ $18.50

$22__ $19.50

$23__ $20.50

Using a linear regression calculator :

The linear regression model obtained is :

y = -2.5 + x

Where ; - 2.5 = intercept ; gradient / slope = 1

1 a

2 d

3 a

4 c

explanation: