Question

Complete the multiplication: 2EA?
E=[1,2] A=[3,0,2,-1]
the answer choices:.
a) [7 −2]
B. [14 −4]
C. [14 4]

Answer 1

@jim_thompson5910 can u help me

Answer 2

i think the answer is b is that correct?

Answer 3

one moment

Answer 4

The given matrices are these?
\[\Large E = \begin{bmatrix}1\\2\end{bmatrix}\]
\[\Large A = \begin{bmatrix}3 & 0\\2 & -1\end{bmatrix}\]
Is that correct?

Answer 5

or is matrix E supposed to look like this?
\[\Large E = \begin{bmatrix}1 & 2\end{bmatrix}\]

Answer 6

e is supposed to be like the second answer you put

Answer 7

Ok so we have
\[\Large E = \begin{bmatrix}1 & 2\end{bmatrix}\]
\[\Large A = \begin{bmatrix}3 & 0\\2 & -1\end{bmatrix}\]

Answer 8

What results when you multiply E*A ?

Answer 9

you should get a 1x2 matrix

Answer 10

are you familiar with matrix multiplication?

Answer 11

7-2 = 2(7-2) = 14-4

Answer 12

yes i am

Answer 13

You should find that
\[\Large E*A = \begin{bmatrix}1 & 2\end{bmatrix}*\begin{bmatrix}3 & 0\\2 & -1\end{bmatrix}\]
\[\Large E*A = \begin{bmatrix}1*3+2*2 & 1*0+2*(-1)\end{bmatrix}\]
\[\Large E*A = \begin{bmatrix}7 & -2\end{bmatrix}\]
Double both sides to get
\[\Large E*A = \begin{bmatrix}7 & -2\end{bmatrix}\]
\[\Large 2*E*A = 2*\begin{bmatrix}7 & -2\end{bmatrix}\]
\[\Large 2*E*A = \begin{bmatrix}2*7 & 2*(-2)\end{bmatrix}\]
\[\Large 2*E*A = \begin{bmatrix}14 & -4\end{bmatrix}\]

Answer 14

I think that's what you wrote above. Or part of it anyway

Answer 15

yeah thanks

Answer 16

sure thing