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| Question 86136:  I need some help with these graph problems.  I would appreciate some help with solving and graphing these systems. Thank you.
 Solve the system by graphing.
 x+y=4
 -x+y=2
 
 Solve the following systym of linear inequalities by graphing.
 3x+4y<12
 x+3y<6
 x>0
 y>0 (under each of the greater and lesser signs is a line)
 
 Solve the following system of linear inequalities by graphing.
 x+2y<3
 2x-3y<6
 Solve the following system of linear inequalities by graphing
 x-2y>4
 x<4
 Thank you so much for taking your time to help me out. thanks alot.
 Answer by jim_thompson5910(35256)
      (Show Source): 
You can put this solution on YOUR website! 
 | Solved by pluggable solver: Solve the System of Equations by Graphing |  | 
 
 Start with the given system of equations:
 
 
 
  
 
  
 
 
 
 
 In order to graph these equations, we need to solve for y for each equation.
 
 
 
 
 So let's solve for y on the first equation
 
 
 
  Start with the given equation 
 
 
 
  Subtract  from both sides 
 
 
 
  Rearrange the equation 
 
 
 
  Divide both sides by  
 
 
 
  Break up the fraction 
 
 
 
  Reduce 
 
 
 Now lets graph
  (note: if you need help with graphing, check out this solver) 
 
 
 
  Graph of  
 
 
 
 So let's solve for y on the second equation
 
 
 
  Start with the given equation 
 
 
 
  Add  to both sides 
 
 
 
  Rearrange the equation 
 
 
 
  Divide both sides by  
 
 
 
  Break up the fraction 
 
 
 
  Reduce 
 
 
 
 
 Now lets add the graph of
  to our first plot to get: 
 
 
  Graph of  (red) and  (green) 
 
 From the graph, we can see that the two lines intersect at the point (
  ,  ) (note: you might have to adjust the window to see the intersection) |  
 
 
 --------------------------------------------------------------------------
 
 Start with the given system of inequalities
 
   
 
   
 
   
 
   
 
 
 In order to graph this system of inequalities, we need to graph each inequality one at a time.
 
 So lets graph the first inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of   Now lets pick a test point, say (0,0) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in x=0, y=0 
 
  Simplify 
 
 Since this inequality is true, we shade the entire region containing (0,0)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 
 
 
 
 Now lets graph the second inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of   Now lets pick a test point, say (0,0) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in x=0, y=0 
 
  Simplify 
 
 Since this inequality is true, we shade the entire region containing (0,0)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 
 
 
 
 Now lets graph the third inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of  (it is the same line as the axis) Now lets pick a test point, say (1,0) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in x=1 
 
  Simplify 
 
 Since this inequality is true, we shade the entire region that contain (1,0)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 
 
 
 
 Now lets graph the fourth inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of  ((it is the same line as the axis) Now lets pick a test point, say (0,1) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in y=1 
 
  Simplify 
 
 Since this inequality is true, we shade the entire region that contain (0,1)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 So we essentially have these 4 regions
 
  Region #1 which is the graph of   
  Region #2 which is the graph of   
  Region #3 which is the graph of   
  Region #4 which is the graph of   
 
 So these 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.
 
   Here is a cleaner look at the intersection of regions
 
 
  Here is the intersection of the 4 regions represented by the dots 
 --------------------------------------------------------------------------
 
 Start with the given system of inequalities
 
   
 
   
 
 
 In order to graph this system of inequalities, we need to graph each inequality one at a time.
 
 So lets graph the first inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of   Now lets pick a test point, say (0,0) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in x=0, y=0 
 
  Simplify 
 
 Since this inequality is true, we shade the entire region containing (0,0)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 
 
 
 
 Now lets graph the second inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of   Now lets pick a test point, say (0,0) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in x=0, y=0 
 
  Simplify 
 
 Since this inequality is true, we shade the entire region containing (0,0)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 So we essentially have these 2 regions
 
  Region #1 which is the graph of   
  Region #2 which is the graph of   
 
 So these 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.
 
   Here is a cleaner look at the intersection of regions
 
 
  Here is the intersection of the 2 regions represented by the dots 
 --------------------------------------------------------------------------
 
 Start with the given system of inequalities
 
   
 
   
 
 
 In order to graph this system of inequalities, we need to graph each inequality one at a time.
 
 So lets graph the first inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of   Now lets pick a test point, say (0,0) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in x=0, y=0 
 
  Simplify 
 
 Since this inequality is not true, we shade the entire region that doesn't contain (0,0)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 
 
 
 
 Now lets graph the second inequality
 
 In order to graph
  we need to graph the equation  (just replace the inequality sign with an equal sign). So lets graph the line  (note: if you need help with graphing, check out this solver) 
  graph of   Now lets pick a test point, say (0,0) (any point will work, but this point is the easiest to work with), and evaluate the inequality
   
  Plug in x=0, y=0 
 
  Simplify 
 
 Since this inequality is true, we shade the entire region containing (0,0)
 
 
 
   Here is the graph of
  with the graph of the line(  ) in red and the shaded region in green (note: In this case, the red line is a solid line. This means the boundaries are included in the region.)
 So we essentially have these 2 regions
 
  Region #1 which is the graph of   
  Region #2 which is the graph of   
 
 So these 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.
 
   Here is a cleaner look at the intersection of regions
 
 
  Here is the intersection of the 2 regions represented by the dots
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