Question

solve the matrix equation PLEASE HELP
5x+6y=14
4x-y=17

Answer 1

familiar with cramers rule?

Answer 2

no kinda can u help

Answer 3

\[\left[\begin{matrix}5 & 6\\ 4 & -1\end{matrix}\right]\left(\begin{matrix}x \\ y\end{matrix}\right) = \left(\begin{matrix}14 \\ 17\end{matrix}\right)\]
AX=B

Answer 4

can u explain?

Answer 5

can you find the determinent of A ?

Answer 6

no :(

Answer 7

you dont know how to find determinent? and u have to solve this through matrix? are you sure about it?

Answer 8

Well, to make it brief, to get the determinant of a 2x2 matrix
\[\left[\begin{matrix}a & b \\ c & d\end{matrix}\right]\]
its determinant is given by
ad - bc

Answer 9

Okay?
So for instance, if we have the matrix
\[\left[\begin{matrix}2 & 6 \\ -1 & 5\end{matrix}\right]\]
Its determinant is
(2)(5) - (-1)(6)
= 16

Answer 10

so what do u get?

Answer 11

hold on :D
Let's just put that equation up again :D
5x + 6y = 14
4x - y = 17

Now, construct the matrix where its components are the respective coefficients of x and y.
(I realise that's vague, so here's how to do it)
If your equations are of the form
ax + by = h
mx + ny = k
Then your matrix A is of the form
\[A = \left[\begin{matrix}a & b \\ m & n\end{matrix}\right]\]

Answer 12

All right, I'll do that then...
But please find its determinant, we need it for future use.
Your matrix A is given by
\[A = \left[\begin{matrix}5 & 6 \\ 4 & -1\end{matrix}\right]\]
any questions?
If none, then please proceed to finding its determinant :D

Answer 13

okay more help?

Answer 14

Formula for determinant was given above... please refer to it :D
I also gave an example.
Here's a refresher
For a matrix M
\[M=\left[\begin{matrix}w & x \\ y & z\end{matrix}\right]\]
Its determinant is given by this formula :
wz - yx

Answer 15

okay so would u get 4 and -1

Answer 16

Those are the coefficients of x and y respectively in the second equation, right? I put them in their proper places in the matrix A, as shown above. Could you find the determinant of A?

Answer 17

no help

Answer 18

@bri4life14 you're excellent of saying "NO" !!!

Answer 19

Again, here's the sample matrix
\[\left[\begin{matrix}2 & 6 \\ -1 & 5\end{matrix}\right]\]
You multiply the upper left component to the lower right
2 x 5
you get
10
From that, you subtract the product of the lower left component and the upper right
10 - (-1)(6)
10 + 6
16
Get it?

Answer 20

thanks

Answer 21

Hey, @bri4life14
That was just an EXAMPLE
I'd still prefer you evaluate the determinant of
\[A = \left[\begin{matrix}5 & 6 \\ 4 & -1\end{matrix}\right]\]on your own, I know you can do it :)

Answer 22

oh yea i know thanks @terenzreignz you have been very helpful :) but @Chlorophyll your rude and you can keep your comments to your self... if your not going to help get off my problem!