Algebra1 formula, what does y2 - y1 over x2 - x1 mean?

That forumula is for calculating a slope (Change in Y over change in X).

Right now for the coordinates 0,2 and 1,4 your slope is 1/2.

4-2/1-0 = 2/1

Which means you'll go up 2, over 1.

This formula is used to determine the slope of a line. The slope of a line (which is commonly called m) is the rise of the line (x2-x1) over the run of that same line (y2-y1). You can use this formula to find other coordinates on the same line if you have a single point and the slope or 2 points, then you can figure out the slope using this formula to find other unknown coordinates

(y2-y1)/(x2-x1) is the gradient of the line.

The equation of the line is y = m x

m = (4-2)/(1-0)=2

so the equation is y=2x

You arent multiplying by o... it is telling you the numbers you need to punch in to figure out slope. on a graph, the first dot would be at the locus of 0 left, and two up. (0,2) and the second would be at 1 right and four up (1,4). WIth these numbers you can graph the line, or determine slope intercept etx.

in the second equation m=2 tells you that slope is m. It is a formula again for determining slope intercept.

By divisibility; y-y=0;x-x=o and 0 divided by 0 is 1 and 0/0 +0/0 =2

thats the example in my book but i dont understand how that could work if anything multipied by 0 is 0

what do you want to multiply?

y2-y1 divided by x2-x1, so it would be y1 over x1, simplified, it would be x over y

these represent two points on a line and are used to determine - "m", the slope of the line. x and y are the axis variables