Question

question will be attached

Given the matrices A and B below, find A + B and 3A

Answer 1

to find A + B you just add by position so
[3 -3;10 9/5;10 -1]

Answer 2

and 3A is just multiplying each entry by 3
so
[6 -9; 0 15; 21 -6]

Answer 3

understand?

Answer 4

so I will just have to add the numbers up across? [2+ (-3)]?

Answer 5

no no
2+1

Answer 6

the top left of A with the top left of B

Answer 7

then put that in the top left of the new matrix

Answer 8

\[\left[\begin{matrix}a & b \\ c & d\end{matrix}\right]+\left[\begin{matrix}e & f \\ g & h\end{matrix}\right]=\left[\begin{matrix}a+e & b+f \\ c+g & d+h\end{matrix}\right]\]

Answer 9

\[3\left[\begin{matrix}a & b \\ c & d\end{matrix}\right]=\left[\begin{matrix}3a & 3b \\ 3c & 3d\end{matrix}\right]\]

Answer 10

ohh ok I get it now thank you :)
then for 3A I just multiply each by 3?

Answer 11

yes

Answer 12

multiplying matrices is a different story and its not as easy, but a constant times a matrix is easy

Answer 13

we call the later scaling the matrix by a factor of 3

Answer 14

ok got it, thank you very much :)

Answer 15

np