Question

Given the matrices A and B below, find A + B find 3A.
A=(2 -3)
(0 5)
(7 -2)
B=(1 0)
(10 -1/2)
(3 1)

Answer 1

Are you confused about how to do this?

Answer 2

yes i dont understand what the question is asking me to do

Answer 3

For matrix addition:

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

Answer 4

So just add the corresponding elements and put the sum in the same position as the original elements.

Answer 5

so then would it be
(3 7 )
(10 4.5)
(10 -1)

Answer 6

but in the right format

Answer 7

Not quite. The first column is correct. The second isnt

Answer 8

and for the 3A one should i just multiply everything in the A matrace by 3?

Answer 9

yes, that is right for the multiplication.

Answer 10

I don't think the first number should be a 7 in column 2 unless you mean for the second matrix to have a 10 not a 0.

Answer 11

oh right it should be -3

Answer 12

oh right it should be -3

Answer 13

yep. That's all there is to it.

Answer 14

\[A+B=\left( \begin{array}{cc} 3 & -3 \\ 10 & \frac{9}{2} \\ 10 & -1 \end{array} \right)\text{, } 3A=\left( \begin{array}{cc} 6 & -9 \\ 0 & 15 \\ 21 & -6 \end{array} \right) \]