# "Writing linear equations given the slope and a point"

• Jan 23rd 2008, 04:58 PM
Forkmaster
"Writing linear equations given the slope and a point"
This was discussed in class, and i got all but 2 or 3 problems done, and then ended up with a stomach bug and missed the Q&A day for the assignment, so i'm asking here. the photobucket links are scans of the graphs, cause i dont know how to describe them, as i barely remember what we're asked of...

Write an equation of the line shown in the graph.

I need 24, and 26. i got the rest...

http://i218.photobucket.com/albums/c...athProblem.jpg

The answers i already had for this type of problem were in the style of y=1/2x+3/2, and y=3/5x, with #/# being fractions, if it helps any...
• Jan 23rd 2008, 05:12 PM
andrew2322
Hello
To solve for the equations of these graphs all you simply do is get two points located on the line. In the case of the first one (Question 24): (-2,2) and (1,0). Now you label each point as a value x1 or x2 or y1 or y2. In this case -2 will be x1 and 2 will be y1. Since x1 and y1 are now taken up 1 will be x2 and 0 will be y2.

Now we find the gradient: y2 - y1 / x2 - x1
This gives us 2 / -3 or -2/3

We then sub it into the equation formula

y - y1 = m(x - x1) [M is the gradient]

y - 0 = -2/3 (x + 2)

and you can take it from there ;)