Please help I don't understand. Also please leave an explanation so I know you are not just lying.

What are the soultion(s) to the quadratic equation 40- x^2=0

Joe has a rectangular chicken coop. the length of the coop is 4 feet less than twice the width. the area of the chicken coop is 510 square feet. what is the length of the chicken coup?

An 18% discount on a watch saved a shopper $72. find the price of the watch before the discount