Question

50 points! I would appreciate an explanation, I actually want to know how to do this. Thanks! :P

Answer 1

1.

(a) The Domain is the set of inputs of the function.

Considering that the function takes a period of 3 weeks (21 days), the domain is [0, 21], once we can't evaluate what happens after the 21st day.

`\text{Domain is } [0, 21]`

Otherwise, it could be
`[0, \infty)`

Note: We include 0 and 21.

Once the greatest balance was $400, it will not exceed $400, either it doesn't show negative values.

`\text{Range is } [0, 400]`

Note: We include 0 and 400.

(b)

Once the greatest balance was $400, when x=0, it seems that the y-value is half of $400, therefore, approximately $200. It also represents the initial value, the amount of money when she opened the account.

(c)

`f(x)=B(d)`

`B(12)=0`

(d)

It is in segment 4.

The balance equal to zero means that the y-value of the graph is zero, therefore in the x-axis.