Quote:
Originally Posted by tags r dumb  slope=change in y value/change in x value=rise over run or slope
so
(-6,9) and (-11,-4)
9-(-)4=13 (change in y value)
-11-(-)6=5 (change in x value)
so 13/5=y/x=rise over run
so the slope is 13/5 so rise 13 run 5, slope =13/5
so use one of your coordinates and plug in with y=mx+b
-6,9
x, y
y=13/5(-6)+9=-6.6, which you have to convert the decimal to an improper fraction, then you have your equation solved...
I hope i helped, its been about 4 years since my last math class in highschool. Im in calc now and i cant remember the last time i did algebra |
You made a mistake when you subbed it into y=mx+b. You used the y value for b; the value of b should be the y-intercept value.
Here's the correct equation with explanations:
(-6,9) and (-11,-4)
First you find the slope between the two points:
m=delta y/delta x
m = (-4-9)/(-11-(-6))
m = -13/-5
m = 13/5
Then, since you have the slope and you also have two usable points that the line goes through, you sub it into this formula:
y=m(x-p)+q
Where m is the slope, y and x are left as they are, p is the x value of one point (TIMES -1, so it's sign will be opposite of what the x value is for the graph), and q is the y value of the same point.
y=m(x-p)+q
y=13/5(x+6)+9
y=13/5x+78/5+45/5
y=13/5x+123/5
y=2.6x+24.6
So, the equation of the line that contains the points (-6,9) and (-11,-4) is y=2.6x+24.6.