Question

Your parents gave you a gift card for your favorite coffee shop. The card was worth $50 when you got it. Each day, you buy a drink for $3. Which equation shows the value on the gift card over time?

A. y = -3x – 50
B. y = -3x + 50
C. y = 3x – 50
D. y = 50x – 3

Answer 1

B

Detailed Explanation

Let's break down this question.

"The card was worth $50 when you got it"

+50

"Each day, you buy a drink for $3"

-3x

The equation that best correlates with the problem is B

Answer 2

B.
`y=-3x+50`

Explanation:

Let x be number of days and y be value of card.

It has been given that your parents gave you a gift card for your favorite coffee shop. The card was worth $50 when you got it. Each day, you buy a drink for $3.

We can see that value of card is dependent on number of days as value of card decrease by 3 each day. This means that slope of our line will be -3.

As initially you have $50, this means that y-intercept of our given line will be 50.

Since we know that equation of a line in slope-intercept form is:
`y=mx+b`, where,

m = Slope of line.

b = y-intercept.

Upon substituting our given values in slope intercept form of equation we will get,

`y=-3x+50`

Therefore, the equation
`y=-3x+50` shows the value on the gift card over time.