Answer/Discussion
to 1a
(3, 5) and (-1, -8)
*Simplify
Answer/Discussion
to 1b
(4, 2) and (4, -2)
*Plug in x and y values into slope formula
*Simplify
Answer/Discussion
to 2a
First, we need to write it in the slope/intercept form:
*Inverse of mult. by 4 is div. by 4
*Written in slope/intercept form
It looks like our slope is -1/2 and our y-intercept is 2.
Answer/Discussion
to 2b
x = -2
Note how we do not have a y. This
type of linear equation was shown in Tutorial
14 (Graphing Linear Equations). When we have x = c, where c is
a constant, then this graph is what type of line?
If you said vertical, you are correct.
Since this is a special type of linear equation that can't be written in the slope/intercept form, I'm going to give you a visual of what is happening and then from that let's see if we can't figure out the slope and y-intercept.
The graph would look like this:
Now, let's look at the y-intercept. Looking at the graph, you can see that this graph never crosses the y-axis, therefore there is no y-intercept either. Another way to look at this is the x value has to be 0 when looking for the y-intercept and in this problem x is always -2.
Final answer, the slope is undefined and the y-intercept does not exist.
Answer/Discussion
to 2c
y = -1
Note how we do not have an x. This
type of linear equation was shown in Tutorial
14 (Graphing Linear Equations). When we have y = c, where c is a constant, then this graph is what type of line?
If you said horizontal, you are correct.
Since this is a special type of linear equation that can't be written
in the slope/intercept form, I'm going to give you a visual of what is
happening and then from that let's see if we can't figure out the slope
and y-intercept.
The graph would look like this:
Now, let's look at the y-intercept. Looking at the graph, you can see that this graph crosses the y-axis at (0, -1). So the y-intercept is (0, -1).
The slope is 0 and the y-intercept is -1.
Answer/Discussion
to 3a
and 
Rewriting the first equation in slope/intercept form we get:
It appears that these slopes are negative reciprocals of each other, so that means the lines would have to be perpendicular to each other.
Answer/Discussion
to 3b
and 
The equations are already in the slope/intercept form, so let's go right to looking for the slope. What did you find?
I found that the slope of the first equation is -5 and the slope of the second equation is 1/5. So what does that mean?
Well, since the two slopes are negative reciprocals of each other, the lines have to be perpendicular.
Answer/Discussion
to 4a
The slope = rise/run = 5/3.
Last revised on July 3, 2011 by Kim Seward.
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