Question

Solve each inequality. Describe the solution set using set-builder or interval notation. Then graph the solution set on number line.

28. $-4\left(5w-8\right)<33$

Short answer

Solution of inequality $-4\left(5w-8\right)<33$ is $w>-\frac{1}{20}$

In interval form, solution set is $\left(-\frac{1}{20},\infty \right)$

Solution set on number line is

Step-by-step solution

- Write properties of inequality

Properties of inequalities are written in following table:

- Simplify −45w−8<33

To simplify given inequality, use subtraction and division property of inequalities. Subtract same numbers from both sides does not change the sign of inequality. Also divide by same negative number reverse the sign of inequality as shown below

$\begin{array}{c}-4\left(5w-8\right)<33\\ -20w+32<33\\ -20w+32-32<33-32\\ -20w<1\\ \frac{-20w}{-20}>\frac{1}{-20}\\ w>-\frac{1}{20}\end{array}$

- Write solution set

The solution set of the inequality contains all real numbers greater than $-\frac{1}{20}$

As, $-\frac{1}{20}$ is not included in the set so parentheses is used with it also $\infty$ is not included so parentheses is used with it.

In interval form solution set is $\left(-\frac{1}{20},\infty \right)$

- Graph the solution set

Assolution set of the inequality is all real numbers greater than $-\frac{1}{20}$

So arrow is towards $\infty$ and open circle on $-\frac{1}{20}$ shows it is not included in the solution set.