Question

Lily has $45 in her school lunch account. If she spends $2.50 each day, which graph represents Lily's account balance, y, after she buys lunch for x days?

Answer 1

y = -2.5x + 45
^ That's your equation. Your y-intercept would be 45 because that's what she started with. It would be a negative slope as well.

Answer 2

`y=-2.50x+45`

Explanation:

Lily has $45 in her school lunch account.

Let the days she buys lunch be = x

And each lunch costs $2.50

So, the equation to know Lily's account balance 'y' will be :

`y=45-2.50x` OR in order,
`y=-2.50x+45`

The graph is attached below.

We can further see that $45 will go on for 18 days.