If using the method of completing the square to solve the quadratic equation x2 + 20x + 28 = 0, which number would have to be

added to "complete the square"?

Asunflower was 20 1/2 inches tall. over the next 6 months, it grew to a height of 37 inches tall. what was the average yearly growth rate of the height of the sunflower? ? plz write a proportion to solve i will give you 100 points