Solve the inequality. Graph and check your solution.

$3r\ge 21$

In this type of inequality, Simply use the property of addition or subtraction or multiplication or division of suitable number on both Left Hand Side & Right Hand Sideto maintain the inequality and also the variable & numbers should be at the different sides in the equation.

Since, the equality is $3r\ge 21$.

Here, to simplify this inequality, divide $3$ to both side on the above

Since, in the expression $r\ge 7$

So, this expression means that the value of r should be greater than or equal to 7.

So, Put $8,9,10,.......so on$in $3r\ge 21$to check whether the inequality hold or not

Put $r=8$in inequality,

$\begin{array}{l}3r\ge 21\\ 3\times 8\ge 21\\ 24\ge 21\end{array}$

It holds the equation

Again, put $r=9$in equality

$\begin{array}{l}3r\ge 21\\ 3\times 9\ge 21\\ 27\ge 21\end{array}$

It also holds the inequality.

So, the expression $r\ge 7$correctly holds the inequality.

Graphical Interpretation

Following is the graph of the expression $r\ge 7$ to get the proper graphical representation to know the points.