Question 110813
Things that I know are a straight line function tend to be
very mechanical in nature, and very predictable. An example
is the number of rotations of a wheel on my car and how far
the car goes on the road.
A linear equation has the form {{{y = mx + b}}} m is the slope
b is allowed to be zero if y = 0 when x = 0.
Say I go 1 mile when the wheel rotates 2,500 times.
Then the car goes 2 miles when it rotates 5,000 times
The equation is {{{y = 2500x}}} where y is miles and x is
nymber of rotations. Y, the vertical axis is always the 
thing that DEPENDS on the other. miles travelled DEPEND on
tire rotations.