Posted by Mathilde on Wednesday, February 20, 2008 at 3:13pm.
3a. The y intercept is the value of y where x equals zero (where the trend line intercepts the y axis).
3b. Pick any other point on the trend line (besides the y intercept) and compute the slope as the change in y divided by the change of x.
ok, for 3b, I would need to divide any point in the x axis by a point on the y axis? Or is that wrong?
3a. The y-intercept is found when you set x to = 0. The y-intercept is the point where the graph of the line crosses the y-axis.
SAMPLE:
In the equation y = 3x + 5, what is the y-intercept?
It is the point (0,5). Do you see number 5? That number represents the y-intercept when x = 0.
Don't trust me?
Here it is:
Let x = 0.
y = 3(0) + 5
y = 0 + 5
y = 5
So, y became 5 when we set x to = 0.
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3b. Pick any two points on the line and find the slope of the line.
The slope is a numerical value that describes just how slanted a given line is.
Here is is an example of finding the slope of a line.
SAMPLE:
Given the points (3, 4) and (8, 9), find the slope.
The symbol for slope is the letter m.
Let m = slope.
We now subtract b from d and a from c.
(a,b) = (3,4)
(c,d) = (8,9)
m = (9 - 4)/(8 - 3)
m = 5/5
m = 1
The slope is 1.
Did you follow?
Yep, thank you VERY much! Except that I don't really get 3a...
P(2,0) Q(4,4)