Question

Evaluate each expression if a=-5,b=6 and c=2.8

$\left|-3a\right|$

Short answer

The absolute value of expression is$\mathbf{15}$.

Step-by-step solution

Step1- Order of evaluation

To evaluate any expression involving one operation, follow the below order of operation

• First replace the algebraic expression inside the grouping symbols like matrix brackets ( $\left|\right|$) with numeric expression

• Perform multiplication in the bracket

• Evaluate the absolute value

Step2- Simplify the expression inside grouping symbol

To evaluate the value of given expression , simply the expression inside the bracket and then find the absolute value of expression as shown below

$\begin{array}{l}|-3a|\\ |-3\times -5|=\left|15\right|\end{array}$

Step3- Find the absolute value of expression inside the bracket

The absolute value of $\left|15\right|=15$.