Answer:
C. From a starting point of 5 meters below sea level, the whale is descending 9 meters per second.
Explanation:
Which statement best describes the depth of the whale, given this equation?
A. From a starting point of 9 meters below sea level, the whale is descending 5 meters per second.
B. From a starting point of 9 meters below sea level, the whale is ascending 5 meters per second.
C. From a starting point of 5 meters below sea level, the whale is descending 9 meters per second.
D. From a starting point of 5 meters below sea level, the whale is ascending 9 meters per second.
Solution:
A linear equation is an equation in the form y = mx + b, where m is the rate of change (slope) and b is the initial value of y when x = 0, y is a dependent variable and x is an independent variable.
Given that: y = -9x - 5
Comparing with the equation of a straight line, m = -9 and b = -5
Since m = -9, The negative sign means descending, therefore the whale is descending at 9 meters per second.
b = -5, the negative sign means below sea level, hence the starting point of the whale is 5 meters below sea level,