 |
STANDARD: Algebra
LEVELS: M - MH
PURPOSE: Apply rule for finding slope from 2 points. (see tutorial for proof)
STRATEGY: The rule says that slope can be found from 2 points by finding "the difference of the y's over the difference of the x's". You must take the difference in the same order
either x & y in 1st point from x & y in 2nd point
or x & y in 2nd point from x & y in 1st point
For example,
.jpg)
The slope is 1/1 or -1/-1 or 1
Notice the answer is the same, whichever way you find the differences. Just do the same order between points.
HINT: Decide which is the easiest!
NO SLOPE: points (4, 3) & (1, 3) become
3 - 3 over 1 - 4 = 0 / - 3
slope (m) = 0 or no slope
This is a horizontal line & the
y coordinate is always 3
(or can do as 3 - 3 over 4 - 1 = 0 / 3)
UNDEFINED: points (-1, 9) & (-1, -1) become
-1 - 9 over -1 - (-1) = -10 / 0
Slope (m) = "undefined"
Division by zero is considered undefined.
This is a vertical line where every
x will be -1; this is not a function.
(or can do as 9 - (-1) over -1 - (-1) = 10 /0)
A graphic organizer to remember 0 and division:
.jpg)
DIRECTIONS: Apply the rule using either rule and write the slope |
