Question

Evaluate the expression when $x=3,y=4,\text{\hspace{0.17em}and}z=5$

localid="1648626124783" $7z-x^2$

Short answer

The value of expression is26.

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 – Substitute the values

To evaluate the expression $7z-x^2$, substitute 3 for x and 5 for z, and simplify further using the order of operations as shown below,

$\begin{array}{c}7z-x^2=7\left(5\right)-{\left(3\right)}^2\\ =7\left(5\right)-9\\ =35-9\end{array}$

Step-3 – Subtract the numbers

To simplify further, subtract the resulting numbers to get

$\begin{array}{c}7z-x^2=7\left(5\right)-{\left(3\right)}^2\\ =7\left(5\right)-9\\ =35-9\\ =26\end{array}$

So, the value of the expression is 26.