4a+6b=10
2a-4b=12

what does 12a =?

How do you solve a question like this?

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

Which word in the sentence below is an interrogative pronoun? who is picking us up from school? whousisfrom