What’s the answer and how do i solve it ?

In the rectangle below ac=30 units what is de

Solve each equation using the quadratic formula. find the exact solutions. 6n^2 + 4n - 11

Adecorative window is made up of a rectangle with semicircles at either end. the ratio of ad to ab is 3: 2 and ab is 30 inches. what is the ratio of the area of the rectangle to the combined area of the semicircles? possible answers: a. 2: 3 b. 3: 2 c. 6: π d. 9: π e. 30: π