SOLUTION: This is not from a book, it's from my teacher. I've been trying to get this right, but I know it's wrong. My teacher wants this: On a four quadrent grid, the following formulas:

Question 46613: This is not from a book, it's from my teacher.
I've been trying to get this right, but I know it's wrong.
My teacher wants this:
On a four quadrent grid, the following formulas:
y= mx+b
(y2-y1)
m= --------
(x2-x1)
A point consists of (x,y)
Two points are written like (x1, y1), (x2, y2)
And equations of the lines for those points.
Does this make any sense to anyone?
Thank you in advance for any help you can offer.
Holly
Answer by adamchapman(301) (Show Source): You can put this solution on YOUR website!
The four quadrant grid is just a normal square grid like the one below:

Each of the squares in the top left, top right, bottom left and bottom right corners are called quadrants.
The eqautaion is the equation of a straight line. is the gradient of that line, and is the y-axis intercept. The y-axis intercept is the value of y when x=0.
Try to remember this equation:
where (x1,y1) and (x2,y2) are points on the line. It is an EXTREMELY important equation.
Lets do an example:
(x1,y1)=(1,2)
(x2,y2)=(3,4)
substitute these values into :
and then rearrange to give y in terms of x:

so comparing with "y=mx+b", m=1 and b=1.
I hope this helps,
Adam.
P.S. please check out my website, it may be helpful to you:
http://www.geocities.com/quibowibbler

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