Seven times a number is 4200. what was the number?

7x+8y=-18, 4x-9y=-3 solve the system of equations

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?

5. (03.02)if g(x) = x2 + 3, find g(4). (2 points)1619811