Chapter 8.1, Problem 81CCR

To determine

The value of the expression $3^2\left[15-\left(-9\right)\right]$

Answer to Problem 81CCR

The value of the expression is $216$

Explanation of Solution

Given:

  $3^2\left[15-\left(-9\right)\right]$

Concept Used:

Rules of Addition/ Subtraction:

• Two numbers with similar sign always get added and the resulting number will carry the similar sign.
• Two numbers with opposite signs always get subtracted and the resulting number will carry the sign of larger number.

Rules of Multiplication/ Division:

• The product/quotient of two similar sign numbers is always positive.
• The product/quotient of two numbers with opposite signs is always negative.

Calculation: In order to find the value of expression $3^2\left[15-\left(-9\right)\right]$ as below:

  $\begin{array}{c}{3}^2=3\ast 3=9\\ \text{So the experssion will become}\\ 3^2\left[15-\left(-9\right)\right]\\ =9\left[15-\left(-9\right)\right]\\ =9\left[15+9\right]\\ =9\left[24\right]\\ =9\cdot 24\\ =216\end{array}$

Thus, the value of the expression is $216$