Answer:
5
Step-by-step explanation:
There are 9 friends with 4 or 5 pets so, you subtract 9-4 because there are 4 friends with 2 or 3 = 5 because the question is asking how many more.
The answer is not defined.
Explanation:
The given matrix is ![$\left[\begin{array}{cc}{2} & {4} \\ {1} & {-6}\end{array}\right]+\left[\begin{array}{c}{1} \\ {0}\end{array}\right]$](https://tex.z-dn.net/?f=%24%5Cleft%5B%5Cbegin%7Barray%7D%7Bcc%7D%7B2%7D%20%26%20%7B4%7D%20%5C%5C%20%7B1%7D%20%26%20%7B-6%7D%5Cend%7Barray%7D%5Cright%5D%2B%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D%7B1%7D%20%5C%5C%20%7B0%7D%5Cend%7Barray%7D%5Cright%5D%24)
The matrix
has dimensions 
This means that the matrix has 2 rows and 2 columns.
Also, the matrix
has dimensions 
This means that the matrix has 2 rows and 1 column.
Since, the matrices can be added only if they have the same dimensions.
In other words, to add the matrices, the two matrices must have the same number of rows and same number of columns.
Since, the dimensions of the two matrices are not equal, the addition of these two matrices is not possible.
Hence, the addition of these two matrices is not defined.
Answer:

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The smallest number of pencils and erasers and 1 eraser per pencil so number of pencils and erasers are equal
*GCD( 12;10) = 60
So Philip buy 60÷12=5 packages of erasers
60÷10=6 packaes of pencils