Question

Jessica opened a savings account with $40.00.

She is going to add $20 per week over the twelve weeks of summer. She will close the account when the summer is over.

Which expression would be an appropriate domain for this situation?

Answer 1

Check the picture below.

so for the equation y = 40 + 20x, what's an appropriate domain? or namely, what could be some valid values for "x"?

well, Jessica is going to put in 20 bucks only for 12 weeks, so whatever "x" is going to be, is must be from 0 to 12, or in interval notation [0 , 12].