Question

The difference in elevation of a helicopter and a submarine is 18 1/2 meters. The elevation of the submarine is -7 3/4 meters. Write and solve an equation to find the elevation h (in meters) of the helicopter

Answer 1

The helicopter is above sea level and the sub below sea level.  

One way in which to write an equation here is |-7  3/4 meters| + h = 18  1/2.

Answer 2

let the elevation of the submarine = s, and elevation of the helicopter = h

the difference in elevation = h - s = 18 1/2

the question gives us the value of s: -5 3/4

so sub that into our first equation

h - (-5 3/4) = 18 1/2
h + 5 3/4 = 18 1/2
h = 18 1/2 - 5 3/4
h = 12 3/4

hope it helps :)