SOLUTION: I've been trying to figure a few of these equations all day, but I can't seem to understand the how to find the slopes and graphs and I'm getting more homework than I can keep up w

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Question 80689: I've been trying to figure a few of these equations all day, but I can't seem to understand the how to find the slopes and graphs and I'm getting more homework than I can keep up with. Also is there a more simple explanation of how to find whether points are parallel or perpendicular? Is there a way I can get some one on one tutoring, either from here or another program?
-find the slope of any line perpendicular to the line through points (0,5) and
(-3,-4)
-Floor plans for a building have the four corners of a room at the points (2,3),(11,6),(-3,18) and (8,21).
Determine whether the side through the points(2,3) and (11,6) is perpendicular to the sides through the points (2,3) and (-3,18).

Answer by jim_thompson5910(21667) About Me  (Show Source):
You can put this solution on YOUR website!
First lets find the slope through the points (0,5) and (-3,-4)
note: check out this solver to get more help with finding the slope

Solved by pluggable solver: Finding the slope
To find the slope going from (0,5) to (-3,-4) we are going to calculate the change in y over the change in x, or the rise over the run. The change is the difference between the two coordinates. So if the y-coordinate of a point goes from 5 to -4, the change in these numbers is -9 (since -4-5=-9). If the x-coordinate changes from 0 to -3, then the change is -3 (since -3-0=-3). So to calculate the slope we use this formula:
Slope:

m=%28change_in_y%29%2F%28change_in_x%29=rise%2Frun where m is the slope

So now we let y%5B2%5D=-4,y%5B1%5D=5,x%5B2%5D=-3,x%5B1%5D=0Now plug these numbers into the slope formula:

m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29=%28-4-%285%29%29%2F%28-3-%280%29%29+=+-9%2F-3


So after simplification the slope is m=3



Since the perpendicular slope is the negative inverse of the original slope, we can say the perpendicular slope is
m%5Bp%5D=-1%2Fm where m%5Bp%5D is the perpendicular slope

So plug in m=3 to get

m%5Bp%5D=-1%2F3
So the perpendicular slope is

m=-1%2F3


---------------------------------------------------------------
"Floor plans problem"
First lets find the slope through (2,3) and (11,6)

Solved by pluggable solver: Finding the slope
To find the slope going from (2,3) to (11,6) we are going to calculate the change in y over the change in x, or the rise over the run. The change is the difference between the two coordinates. So if the y-coordinate of a point goes from 3 to 6, the change in these numbers is 3 (since 6-3=3). If the x-coordinate changes from 2 to 11, then the change is 9 (since 11-2=9). So to calculate the slope we use this formula:
Slope:

m=%28change_in_y%29%2F%28change_in_x%29=rise%2Frun where m is the slope

So now we let y%5B2%5D=6,y%5B1%5D=3,x%5B2%5D=11,x%5B1%5D=2Now plug these numbers into the slope formula:

m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29=%286-%283%29%29%2F%2811-%282%29%29+=+3%2F9


So after simplification the slope is m=1%2F3



Now lets find the slope through (2,3) and (-3,18)

Solved by pluggable solver: Finding the slope
To find the slope going from (2,3) to (-3,18) we are going to calculate the change in y over the change in x, or the rise over the run. The change is the difference between the two coordinates. So if the y-coordinate of a point goes from 3 to 18, the change in these numbers is 15 (since 18-3=15). If the x-coordinate changes from 2 to -3, then the change is -5 (since -3-2=-5). So to calculate the slope we use this formula:
Slope:

m=%28change_in_y%29%2F%28change_in_x%29=rise%2Frun where m is the slope

So now we let y%5B2%5D=18,y%5B1%5D=3,x%5B2%5D=-3,x%5B1%5D=2Now plug these numbers into the slope formula:

m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29=%2818-%283%29%29%2F%28-3-%282%29%29+=+15%2F-5


So after simplification the slope is m=-3



Notice that the side that contains the points (2,3) and (11,6) has a slope of m=1%2F3. Also notice that the side containing (2,3) and (-3,18) has a slope of m=-3. So to see if they are perpendicular we simply invert and negate either slope. For instance, lets invert and negate the first slope m=1%2F3:

m%5Bp%5D=-1%2Fm

m%5Bp%5D=-1%2F%281%2F3%29=-3

So the perpendicular slope is -3. This shows that -3 and 1/3 are perpendicular slopes which means the two sides are perpendicular.