### Answer:

( -1, -2, 3 )^{T} + ( 1, 2, -3 )^{T} = ( 0, 0, 0 )^{T}

# Zero Column Matrix

Here is a problem which will probably not be on the midterm:

( 73.6, -41.4 )^{T} + ( 0.0, 0.0 )^{T} = (73.6, -41.4 )^{T}

A matrix with all zero elements is sometimes called a **zero matrix**.
The sum of a zero matrix and a matrix **a** of the same type
is just **a**.

In symbols the zero matrix is written as **0** (bold face zero)
which is different
than 0, the real number zero.
The context in which you see **0**
determines whether it is a row or a column and how many elements it has.
So if you see

(73.6, -41.4 )^{T} + **0**

you can assume that **0** is the right type of matrix for the expression.

### QUESTION 6:

Do the following problem (which *might* be on the midterm):

( 2, 5, -9 ) + ( -32.034, 94.79, 201.062 ) + ( -2, -5, 9 ) =