The quotient of any number less 12 and any number added to 12

Measures of the angle of r, 31 s (x+4) t (3x+9)

Which shows the correct substitution of the values a, b and c from the equation 1=-2x+3x^2+1

Sarah took the advertising department from her company on a round trip to meet with a potential client. including sarah a total of 11 people took the trip. she was able to purchase coach tickets for $280 and first class tickets for $1280. she used her total budget for airfare for the trip, which was $6080. how many first class tickets did she buy? how many coach tickets did she buy?