SOLUTION: Solve the following system of linear inequalities by graphing: x-2y<4 x<4

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Question 82579: Solve the following system of linear inequalities by graphing:
x-2y<4
x<4

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Solve the first equation for y:

x-2y%3C4

-2y%3C4-x Subtract x from both sides

y%3E%281%2F2%29x-2 Divide both sides by -2. Remember multiplying or dividing by a negative flips the inequality sign


Now graph both y=%281%2F2%29x-2 and x=4
+graph%28+300%2C+200%2C+-6%2C+5%2C+-10%2C+10%2C+%281%2F2%29x-2%2C+10000%28x-4%29%29+

Lets pick a test point (0,0) and test it with y%3E%281%2F2%29x-2

%280%29%3E%281%2F2%29%280%29-2 Plug in x=0, y=0

0%3E-2 Since this expression is true we shade the entire region containing (0,0) for the inequality y%3E%281%2F2%29x-2. This region is above the line.

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Now lets test x%3C4

x%3C4 Plug in x=0

0%3C4 Since this expression is true we shade the entire region containing (0,0) for the inequality x%3C4. This is the region to the left of the vertical line.
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Notice how these regions overlap. This overlapping region is our final shaded region. Every point in this region satisfies both y%3E%281%2F2%29x-2 and x%3C4
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