India Site

Solve the following system of inequalities graphically: \[x+y\le 9\], \[y>x\] , \[x\ge 0\]

Solution:

The given inequalities are  \[x+y\le 9\], \[y>x\] , \[x\ge 0\]

For \[x+y\le 9\],

Let us put value of \[x=0\] and \[y=0\] in equation one by one, we get

\[y=9\] and \[x=9\]

We get the required points as  \[(0,9)\] and \[(9,0)\]

To check if the origin is included in the line`s graph \[(0,0)\]

\[0\le 9\] Which is true, so the required area would be including the origin and hence will lie on the left side of the line`s graph.

For \[y>x\],Solving for \[y=x\]

We get \[x=0,y=0\]

hence the origin lies on the line`s graph.

We can take the other points as \[(0,0)\]and \[(2,2)\]

Now Checking for \[(9,0)\] in \[y>x\], We get,

\[0>9\]which is false, since the area would not include the area below the line`s graph and hence would be on the left side of the line.

Now we have \[x\ge 0\]

Therefore ,the area of the required line`s graph would be on the right side of the line`s graph.

In the below graph the shaded area in the graph is the required solution of the given inequalities.