Ixl, what are all the right answers?

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

How can you tell when x and y are not directly proportional?

Someone answer asap for ! the boiling point of water at an elevation of 0 feet is 212 degrees fahrenheit (°f). for every 1,000 feet of increase in elevation, the boiling point of water decreases by about 2°f. which of the following represents this relationship if b is the boiling point of water at an elevation of e thousand feet? a. e = 2b - 212 b. b = 2e - 212 c. e = -2b + 212 d. b = -2e + 212