MHB How do you solve and plot inequalities with multiple variables?

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To solve and plot the inequalities 2<x<6, 1<y<5, y-2≤2x, and -2y≥8-4x, the first step involves identifying the regions defined by each inequality. For 2<x<6, dashed lines are drawn at x=2 and x=6, shading the area between these lines. The inequalities y-2≤2x and -2y≥8-4x can be rewritten as y≤2x+2 and y≤-4+2x, respectively, which also need to be graphed. The common shaded area represents the solution set for the system of inequalities. The final graph will visually depict the intersection of all these regions, indicating where all conditions are satisfied.
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I have the inequalities $$2<x<6,\quad 1<y<5,\quad y-2\le2x, \quad-2y\ge8-4x$$ I have to solve these and plot it in a graph and show the region where they satisfy. I understand you have to find the common area and shade it.

How do you find the points to plot for $$2<x<6\quad and\quad 1<y<5$$

I think I have solved $$y-2\le2x\quad and -2y\ge8-4x$$ to $$y\le2x+2\quad and \quad y\le-4+2x$$ I am just unsure on the first two. Will making a X and Y table help to find the points?
 
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Well, the region $2<x<6$ contains all the points in the $x,y$-plane where the $x$-component lies between $2$ and $6$ (both not included).
 
Siron said:
Well, the region $2<x<6$ contains all the points in the $x,y$-plane where the $x$-component lies between $2$ and $6$ (both not included).

If i made a graph, would it go through the $y$ axis diagonal through the points $2$ and $6$?
 
mathsheadache said:
If i made a graph, would it go through the $y$ axis diagonal through the points $2$ and $6$?

For the inequality $2<x<6$, I would begin by graphing the lines $x=2$ and $x=6$ with dashed lines since the inequality is strict on both sides of $x$. Now you have divided the plane into 3 regions. which of these regions should you shade?
 
MarkFL said:
For the inequality $2<x<6$, I would begin by graphing the lines $x=2$ and $x=6$ with dashed lines since the inequality is strict on both sides of $x$. Now you have divided the plane into 3 regions. which of these regions should you shade?

Because it is x>2 is greater than, I shade everything to the right. And becuase x<6 is less than, shade everything to the left? I will be left with a shaded region in between 2 and 6?
 
mathsheadache said:
Because it is x>2 is greater than, I shade everything to the right. And becuase x<6 is less than, shade everything to the left? I will be left with a shaded region in between 2 and 6?

Yes, good! (Sun)

That's what $2<x<6$ means...any value of $x$ on the interval $(2,6)$, i.e., any value of $x$ in between 2 and 6, but not including 2 and 6. :D

So, the region you have shaded contains all the points in the plane for which the $x$-coordinate satisfies the given compound inequality.
 

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