# Linear Graphs

## Main Question or Discussion Point

The question reads: find the value of k to make the points (3,9) (7, k), and (-1,6) collinear.

Does this involve using the distance formula? Whether or not it does, how would I go about solving this problem?

rock.freak667
Homework Helper
The question reads: find the value of k to make the points (3,9) (7, k), and (-1,6) collinear.

Does this involve using the distance formula? Whether or not it does, how would I go about solving this problem?
What does collinear mean? That means that those 3 points lie on the same straight line.
So there are two methods you can use to find k.

You can find the straight line equation through all the points and then sub the co-ord you want to get.

OR you can use what you know about the slope of a line to aid you in an easier fashion.

ok thank u!

question 2

write an equation for the line that contains (0, 3) and is perpendicular to the line 6x-2y=1.

So for this question, i've found the slope of the line 6x-2y=1 which was 3. But would the slope for line (0, 3) be -1/3?

HallsofIvy
Homework Helper
Yes.

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HallsofIvy