Math 111, Fri, Aug 26, 2011

1.3 - Lines and slopes...

slope: change in y / change in x (rise / run)

for , up three each time I go 2 to the right (down three each time I go 2 to the left)

This line has a slope of 2...

If you write a line as , then the m is the slope.

We can find the slope of

so

Also note that when x=0 then and the point is the y-intercept

because of this.. is called "slope-intercept" form of the line

We call "General" form of a line

"Point-slope" form looks like:

Using this we can quickly write a line through with slope

and switch to slope intercept

You but a copier for \$18,000 and it has linear depreciation for 15 years - at which time its scrap value is \$3,000.

dollars per year.

47) The population of Flint, MI decreased from 124,943 in 2000 to 112,900 in 2008... Find the "average rate of change" (slope) in population over that time

people per year

We could even write an equation...

If I call 2000 the year "0"

If I leave 2000 as 2000...

A taxi costs \$3 to pickup and \$2 a mile.

The slope is dollars per mile.

The y-intercept is 3 dollars.