Ijust need to know how to work it out . and you

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39

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

Pyramid shown has a square base that is 18 inches on each side has a surface area of 164 square inches what is the slant height