SOLUTION: they involve graphing, inequalities and systems of equations! Problem 10 is a lot like Check Yourself 3 (p 726)…. 10) 3x – y ≤ 6 x ≥ 1 y ≤

Algebra ->  Linear-equations -> SOLUTION: they involve graphing, inequalities and systems of equations! Problem 10 is a lot like Check Yourself 3 (p 726)…. 10) 3x – y ≤ 6 x ≥ 1 y ≤       Log On


   



Question 89740: they involve graphing, inequalities and systems of equations! Problem 10 is a lot like Check Yourself 3 (p 726)….
10) 3x – y ≤ 6
x ≥ 1
y ≤ 3

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Start with the given system of inequalities
3x-y%3C=6
x%3E=1
y%3C=3

In order to graph this system of inequalities, we need to graph each inequality one at a time.


First lets graph the first inequality 3x-y%3C=6
In order to graph 3x-y%3C=6, we need to graph the equation 3x-y=6 (just replace the inequality sign with an equal sign).
So lets graph the line 3x-y=6 (note: if you need help with graphing, check out this solver)

+graph%28+500%2C+500%2C+-20%2C+20%2C+-20%2C+20%2C+3x-6%29+ graph of 3x-y=6
Now lets pick a test point, say (0,0). Any point will work, (just make sure the point doesn't lie on the line) but this point is the easiest to work with. Now evaluate the inequality 3x-y%3C=6 with the test point

Substitute (0,0) into the inequality
3%280%29-%280%29%3C=6 Plug in x=0 and y=0
0%3C=6 Simplify

Since this inequality is true, we simply shade the entire region that contains (0,0)
Graph of 3x-y%3C=6 with the boundary (which is the line 3x-y=6 in red) and the shaded region (in green)

---------------------------------------------------------------


Now lets graph the second inequality x%3E=1
In order to graph x%3E=1, we need to graph the equation x=1 (just replace the inequality sign with an equal sign).
So lets graph the line x=1 (note: if you need help with graphing, check out this
solver)

+graph%28+500%2C+500%2C+-20%2C+20%2C+-20%2C+20%2C+1000%28x-1%29%29+ graph of x=1
Now lets pick a test point, say (0,0). Any point will work, (just make sure the point doesn't lie on the line) but this point is the easiest to work with. Now evaluate the inequality x%3E=1 with the test point

Substitute (0,0) into the inequality
%280%29%3E=1 Plug in x=0 and y=0
0%3E=1 Simplify

Since this inequality is not true, we do not shade the entire region that contains (0,0). So this means we shade the region that is on the opposite side of the line
Graph of x%3E=1 with the boundary (which is the line x=1 in red) and the shaded region (in green)

---------------------------------------------------------------


Now lets graph the third inequality y%3C=3
In order to graph y%3C=3, we need to graph the equation y=3 (just replace the inequality sign with an equal sign).
So lets graph the line y=3 (note: if you need help with graphing, check out this
solver)

+graph%28+500%2C+500%2C+-20%2C+20%2C+-20%2C+20%2C+3%29+ graph of y=3
Now lets pick a test point, say (0,1). Any point will work, (just make sure the point doesn't lie on the line) but this point is the easiest to work with. Now evaluate the inequality y%3C=3 with the test point

Substitute (0,0) into the inequality
%280%29%3C=3 Plug in x=0 and y=0
0%3C=3 Simplify

Since this inequality is true, we simply shade the entire region that contains (0,0)
Graph of y%3C=3 with the boundary (which is the line y=3 in red) and the shaded region (in green)

---------------------------------------------------------------


So we essentially have these 3 regions:

Region #1
Graph of 3x-y%3C=6


Region #2
Graph of x%3E=1


Region #3
Graph of y%3C=3




When these inequalities are graphed on the same coordinate system, the regions overlap to produce this region. It's a little hard to see, but after evenly shading each region, the intersecting region will be the most shaded in. (note: for some reason, this image and the following image does not display in Internet Explorer. So I would recommend the use of
Firefox to see these images.)







Here is a cleaner look at the intersection of regions




Here is the intersection of the 3 regions represented by the series of dots