Question

A submarine is 4,000 feet below sea level, and rising a rate of 100 feet pre minute. Write an equation to represent y, the depth of the submarine after x minutes.

Answer 1

Answer: -4000+100x=y
Explanation: the submarine is 4000 feet BELOW sea level which is why in the equation there is a negative sign. Then the submarine rises 100 feet per minute and the x represents minutes and y is the depth of the submarine.

Answer 2

• y = 100x - 4000

Explanation:

• Initial elevation is a starting point, therefore y-intercept is -4000
• The rate of change is the slope, therefore m = 100

The equation of the linear function is:

• y = 100x - 4000