Solve the inequality \( 3 x \geq-9 \). Write the solution set in interval notation, and graph it. The solution set is \( \square \). (Simplify your answer.

To solve the inequality \( 3x \geq -9 \), start by dividing both sides by 3. This gives: \[ x \geq -3 \] The solution set can be expressed in interval notation as \([-3, \infty)\). To graph this, you would shade all values to the right of \(-3\) on a number line, including a closed circle at \(-3\) to indicate that \(-3\) is included in the solution set.