SOLUTION: PLEASE HELP I JUST DON'T UNDERSTAND THESE PROBLEMS AND I DON'T KNOW WHAT TO DO. PLEASE HELP ME.... : Graphical Representation of Linear Equations 1. Plot the graph of the equ

Algebra ->  Linear-equations -> SOLUTION: PLEASE HELP I JUST DON'T UNDERSTAND THESE PROBLEMS AND I DON'T KNOW WHAT TO DO. PLEASE HELP ME.... : Graphical Representation of Linear Equations 1. Plot the graph of the equ      Log On


   

Question 163463This question is from textbook elementary and intermediate algebra
: PLEASE HELP I JUST DON'T UNDERSTAND THESE PROBLEMS AND I DON'T KNOW WHAT TO DO. PLEASE HELP ME....
: Graphical Representation of Linear Equations
1. Plot the graph of the equations 3x - 8y = 5 and 4x - 2y = 11 and interpret the result.
2. Plot the graph of the equations 4x - 6y = 2 and 2x - 3y = 1 and interpret the result.
3. Plot the graph of the equations 10x - 4y = 3 and 5x - 2y = 6 and interpret the result.
 This question is from textbook elementary and intermediate algebra

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
: Graphical Representation of Linear Equations
1. Plot the graph of the equations 3x - 8y = 5 and 4x - 2y = 11 and interpret the result.
:
First. you want to get equations into the general form, to plot the graphs
3x - 8y = 5
-8y = -3x + 5
y has to be positive, multiply equation by -1
8y = 3x - 5
Divide equation by 8 to get 1y or just y:
y = 3%2F8x - 5%2F8
and
4x - 2y = 11
-2y = -4x + 11
2y = 4x - 11; multiplied by -1 again
y = 2x - 11%2F2; divided by 2
:
Using these two equation, plot two points for each by substituting a value for x
and finding the value for y (I assume you know how to do that, if not email me)
1st equation: y = 3%2F8x - 5%2F8; Green
x | y
-------
-1 |-1
+3 |+.5;
:
2nd equation: y = 2x - 11%2F2; purple
x | y
------
-2 |-6.2
+3 |+3.8
:
Plot these two graph and it should look like this:
+graph%28+300%2C+200%2C+-6%2C+6%2C+-6%2C+6%2C+2x-5.5%2C+%283%2F8%29x-%285%2F8%29%29+
From the graph we can see that they intersect at x/y coordinates: 3,.5
That is interpreted as the solution to this system of two equations
:
You can prove this, substitute 3, for x and .5 for y i the 1st original equation
3x - 8y = 5
3(3) - 8(.5) = 4
9 - 4 = 5
:
Do the same in the 2nd original equation:
4x - 2y = 11
4(3) - 2(.5) =
12 - 1 = 11
:
We know that these coordinates are the solution to these two equation
:
I am running out of time right now. See how you do, let me know. I will have time later today to work on this. Carl



2. Plot the graph of the equations 4x - 6y = 2 and 2x - 3y = 1 and interpret the result.
3. Plot the graph of the equations 10x - 4y = 3 and 5x - 2y = 6 and interpret the result.