The answer is 7x-3 if you add like terms which are 4x, 2x, and x then take 2, 3, -2 and subtract from each other
Since y is 5.2 you can substitute it in your equations 5.2 = -5x - 40 then you do things like normal add 40 in both sides and divide -5 in both sides you get 9.04
If a submarine is 756 feet below sea level in order to come to 0 sea level it will have to rise as much as it dropped which is 756 feet.
