3, -6, 12, 4, 20, ? what is the next number

3(10x-y)-5(x-y^2) need this solved asap

For what is the measure of the angle at the top of the shed? a. multiplication of areas b. squaring of areas c. addition of areas d. division of areas

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