Which of the following is a flat surface that extends infinitely, has length and width, but does not have depth?

How do i do this activity, is appreciated

Scrub a dub toothbrushes are $4.00 each. there is a 10% discount, but there is also a 6% sales tax after the discount is applied. what is the new price after tax? round to the nearest penny

Which of the following is true for the relation f(x)=2x^2+1