SOLUTION: How would you graph the following? 2x+3y <18 3x-y =/< 6 y =/> 0 x=/> 0

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Question 1109406: How would you graph the following?
2x+3y <18
3x-y =/< 6
y =/> 0
x=/> 0

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
1. 2x%2B3y+%3C18
to graph the following inequality, first draw the line and decide which side to shade for the required region
Explanation:
Treat the inequality as an equality or as a straight line graph first. Then shade the correct side of the line to indicate the solutions which are less than 18.
You can use any method to draw the straight line - plot points or use the intercept/gradient method.
I will use the method of the x and y intercepts.
To find the x-intercept, make y=0:
2x%2B3y+=18
2x%2B3%2A0+=18
2x+=18
x+=+9 => x-intercept is at (9,0)
To find the y-intercept, make x=0
2x%2B3y+=18
2%2A0%2B3y=18+
3y=18
y=+6=> y-intercept is at (0,6)
Now that you have both intercepts you can plot them and draw a solid line through them. This is the line 2x%2B3y+=18.
You could also write the equation as : y=-%282%2F3%29x%2B6
+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+-%282%2F3%29x%2B6%29+
To decide which side of the line to shade, choose a test point.
(0,0) is a good one to test:
since given: 2x%2B3y+%3C18, you have
2%2A0%2B3%2A0+%3C18 => 0%3C18 is true

so, (0,0) is in the required region and the area BELOW the line must be shaded
+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+2x%2B3y+%3C18%29+

2. 3x-y+%3C=6...do it same way

intercepts:
3x-y+=6...set y=0
3x-0+=6
x+=2=> x-intercept is at (2,0)
3x-y+=6...set x=0
3%2A0-y+=6
y+=-6=> y-intercept is at (0,-6)
graph:3x-y+=6 or y=3x-6

+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+3x-6%29+
since given 3x-y+%3C=6 solution is a line and all points to the left and above the line
+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+3x-y+%3C=6%29+

3.
y%3E=+0-> here you have graph shaded above x-axis including x-axis
+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+y+%3E=0%2Cy+%3E=0%29+
4.
x%3E=+0-> here you have graph shaded starting with y-axis including everything to the right
+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+x+%3E=0%2Cx+%3E=0%29+