Question

Help Please. What is the solution of the matrix equation?

[31] [x] [3]
[5 2] [y] = [10]

A.(–6, 4)
b.(6, –4)
c.(4, 15)
d.(–4, 15)

Answer 1

The matrix equation :
\[\begin{pmatrix}3&1\\5&2\end{pmatrix}\begin{pmatrix}x\\y\end{pmatrix}=\begin{pmatrix}3\\10\end{pmatrix}\]
That means :
\[\begin{cases}3x+y&=3~~~~~~~(1)\\5x+2y&=10~~~~~~(2)\end{cases}\]
By multiplying the 1st equation by (1), we get :
\[\begin{cases}6x+2y&=6~~~~~~~(1)\\5x+2y&=10~~~~~~(2)\end{cases}\]
(1)-(2) :
\[x=-4\]
So : \[6(-4)+2y=6\]
SO :
\[-24+2y=6\]
SO :
\[2y=6+24\]
SO :
\[y=30/2=15\]

So the answer is : D

Answer 2

thank you

Answer 3

and by multiplying the first equation by one does not give me 6 @Noura11

Answer 4

He meant to say multiply the first equation by 2.

Answer 5

oo ok

Answer 6

A mistype in the line 5 in my reply !
I am not a computer or a bike ! I am a human !

Answer 7

sorry thank you though @Noura11

Answer 8

I just was joking !

Answer 9

"I am not a computer or a bike ! I am a human !"

Do bikes never make mistakes? :P