# Thread: Solving for x, y, z, w in a matrix

1. ## Solving for x, y, z, w in a matrix

this is my 2nd question in over 12+ hours.

$\displaystyle \left[\begin{matrix}x+y&x+z\\y+z&w\end{matrix}\\]$

Equals

$\displaystyle \left[\begin{matrix}3&4\\5&4\end{matrix}\\]$

i got
x + y = 3 x+z = 5
y + z = 5 w=4

and i don't know what to do from there. text book is really horrible.

2. u always look how u can easy ur task ... u can do like this (or any another)
$\displaystyle x+y=3 \to y=3-x$ 1)
$\displaystyle y+z=5$ 2)
$\displaystyle x+z=5 \to z=5-x$ 3)

1) and 3) in 2) ...

3. Thanks a million yeKciM

4. Originally Posted by mgrexGT1
this is my 2nd question in over 12+ hours.

$\displaystyle \left[\begin{matrix}x+y&x+z\\y+z&w\end{matrix}\\]$

Equals

$\displaystyle \left[\begin{matrix}3&4\\5&4\end{matrix}\\]$

i got
x + y = 3 x+z = 5
y + z = 5 w=4

and i don't know what to do from there. text book is really horrible.
You have four equations in four unknowns: x+ y= 3, x+ z= 5, y+ z= 5 and w= 4.
If you subtract the third equation from the second, you eliminate z: x+ z- (y+ z)= x- y= 0.
Can you solve the two equations x+ y= 3 and x- y= 0?