Answer: the answer would be To make sure they remain effective.
Step-by-step explanation:
It wouldn't be to make sure they are up to code because fire extinguishers do not use code, code is used in electronics. For the second option and the last option it would not be this because they could be trained in a practice instead of using the real thing.
Answer <u>(assuming it is allowed to be in point-slope format)</u>:

Step-by-step explanation:
1) First, determine the slope. We know it has to be perpendicular to the given equation,
. That equation is already in slope-intercept form, or y = mx + b format, in which m represents the slope. Since
is in place of the m in the equation, that must be the slope of the given line.
Slopes that are perpendicular are opposite reciprocals of each other (they have different signs, and the denominators and numerators switch places). Thus, the slope of the new line must be
.
2) Now, use the point-slope formula,
to write the new equation with the given information. Substitute
,
, and
for real values.
The
represents the slope, so substitute
in its place. The
and
represent the x and y values of a point the line intersects. Since the point crosses (1,4), substitute 1 for
and 4 for
. This gives the following equation and answer:

The independent variable is the variable that is being changed. In this statement, it would be water flowing flowing in the pool. The dependent variable is what is being changed so that would be the depth of the water.
There, I hope this helps! :)