Hi pls help me i dont understsnd

The depth of a lake at a certain point, wich is a function of the distance of that point from shore, is 30 feet.

Which expression is equivalent to 2x^2+7x+4?

The sales tax rate is 7.25%. how much tax in dollars is added on an item that costs $56.00? a. $4.06 b. $7.25 c. $14.50 d. $60.06