Find the missing lengths please help for a grade

Barbara deposited $300 in the bank. if the bank pays her simple interest at the rate of 4 percent per year, how much money will she have in her account at the end of 9 months?

You have a square piece of cardboard that measures 14 inches on each side. to build a box, you cut congruent squares out of each corner of the cardboard. use the picture to find the area of the cardboard you were used to build the box

Rewrite the following quadratic functions in intercept or factored form. show your work. y = 9 + 12x + 4x^2