Hellobee Boards

I can't find a video for exactly this type of problem, but you would use a similar strategy to this one

I was a math major in college and LOVE stuff like this! I left a message on your wall.

So, you want to figure out the slop of the line passing through (−2,0) and (−4,−5). The formula for slope is "y2-y1"/"x2-x1". So, -5-0/-4--2 = -5/-2 = 5/2.

To be parallel, the other line must have the same slope. So using (7,k) and (8,−8) gives us: (-8-k)/(8-7) = (-8-k)/1 = 5/2
So, by cross multiplying the fractions, we get 2*(-8-k) = 5
-16-2k = 5
-2k = 21
k = -10.5

You can double check your work: if the slope for both lines is 5/2, then increasing x by 2 means you increase y by 5. Therefore, increasing x by 1 means increasing y by 2.5.
Going from (7, -10.5) to (8, -8) you did exactly that -- x increases by 1, and y increases by 2.5!

It is really hard to type this out , but I'd be happy to email with you or even chat. I tutored math all through college and really enjoy this.