Please help with questions 5-7.

Simplify 15(x - 4)(x -1)-3(x + 4)(x - 1) with steps

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

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