a. If sea level is represented by 0, then something below sea level would be a value of something less than zero, a negative number. Because the Challenger Deep is 35,814 feet below sea level, it will be represented by -35,814.
b. Trieste is trying to reach the bottom of the challenger deep, which is y, and descending the ocean at -3 feet per second. So the equation would be like this
-35,814 = -3x
We are just looking for x. Notice how both number values are negative so the time it would take Trieste to reach the bottom would be a positive value.
-35,814 divided by -3 = 11938, so it would take 11938 seconds to reach the bottom.
c. <em>y</em> and <em>x</em> would be used in the same context as it would just now. Except that Trieste is coming up to the surface, so the depth of the Challenger Deep is positive.
35814 = k * 11938
k = 3, the amount of time it took to reach the surface in hours.
Hope this helps!
