Question

Evaluate the expression when$x=20\text{and}y=5$.

$3(x-y)$

Short answer

The value of the expression is45.

Step-by-step solution

Step 1  . Order of operations

To evaluate any expression involving more than one operation, follow the below order of operations:

• First evaluate expressions inside grouping symbols like parentheses ( ) or brackets [ ].
• Evaluate the exponents.
• Perform Multiplication and division from left to right.
• Perform addition and subtraction from left to right.

Step 2  . Evaluate inside grouping symbol

To evaluate the given expression$3(x-y)$, substitute 20 for x and 5 for y and simplify further as shown below

$\begin{array}{c}3(x-y)=3(20-5)\\ =3\left(15\right)\end{array}$

Step 3  . Multiply the numbers

Now to simplify further, multiply the numbers to get

$\begin{array}{l}3\left(15\right)\\ =45\end{array}$

Thus, the value of the expression is 45.