Question

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

$3\left|a-10\right|+\left|2a\right|$

Short answer

The absolute value of expression is$\mathbf{55}$.

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 the subtraction inside first pair of bracket

• Perform the multiplication inside the second pair of bracket

• Evaluate the absolute values of the pair

• Perform the addition from left to right

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

$\begin{array}{c}3|a-10|+\left|2a\right|=3|-5-10|+|2\times -5|\\ =3|-15|+|-10|\end{array}$

Step3- Find the absolute value of expression inside the bracket and subtract

The absolute value of $\left|-15\right|=15$ and $\left|-10\right|=10$

The solution is,

$\begin{array}{c}3\times 15+10=45+10\\ =55\end{array}$