Chapter 12.1, Problem 9P

Find each sum or difference.

$\left[\begin{array}{l}-21.34.4\\ 01.2-2\\ 42-2.6\end{array}\right]-\left[\begin{array}{l}3.40-0.5\\ 5.28-1.2\\ 2.3-21\end{array}\right]$

To determine

Find the sum or the difference.

Answer to Problem 9P

  $\left[\begin{array}{l}\text{-5}\text{.4 1}\text{.3 4}\text{.9}\\ \text{-5}\text{.2 -6}\text{.8 -0}\text{.8}\\ \text{1}\text{.7 4 -3}\text{.6}\end{array}\right]$

Explanation of Solution

Given:

  $\left[\begin{array}{l}\text{-2 1}\text{.3 4}\text{.4}\\ \text{0 1}\text{.2 -2}\\ \text{4 2 -2}\text{.6}\end{array}\right]-\left[\begin{array}{l}\text{3}\text{.4 0 -0}\text{.5}\\ \text{5}\text{.2 8 -1}\text{.2}\\ \text{2}\text{.3 -2 1}\end{array}\right]$

Formula Used:

  $\left[\begin{array}{l}\text{a b c}\\ \text{d e f}\\ \text{g h i}\end{array}\right]-\left[\begin{array}{l}\text{j k l}\\ \text{m n o}\\ \text{p q r}\end{array}\right]=\left[\begin{array}{l}\text{a-j b-k c-l}\\ \text{d-m e-n f-o}\\ \text{g-p h-q i-r}\end{array}\right]$

Calculation:

  $\left[\begin{array}{l}\text{-2 1}\text{.3 4}\text{.4}\\ \text{0 1}\text{.2 -2}\\ \text{4 2 -2}\text{.6}\end{array}\right]-\left[\begin{array}{l}\text{3}\text{.4 0 -0}\text{.5}\\ \text{5}\text{.2 8 -1}\text{.2}\\ \text{2}\text{.3 -2 1}\end{array}\right]=\left[\begin{array}{l}\text{-2-3}\text{.4 1}\text{.3-0 4}\text{.4+0}\text{.5}\\ \text{0-5}\text{.2 1}\text{.2-8 -2+1}\text{.2}\\ \text{4-2}\text{.3 2+2 -2}\text{.6-1}\end{array}\right]=\left[\begin{array}{l}\text{-5}\text{.4 1}\text{.3 4}\text{.9}\\ \text{-5}\text{.2 -6}\text{.8 -0}\text{.8}\\ \text{1}\text{.7 4 -3}\text{.6}\end{array}\right]$