# Math Help - What makes this matrix true?

1. ## What makes this matrix true?

what makes this matrix true?

$
(\begin{array}{|ccc|}x&2&-1\\0&y&w\end{array}
+ \begin{array}{|ccc|}0&1&2\\0&0&2\end{array})
* \begin{array}{|ccc|}1&1\\3&z\\4&2\end{array}
= \begin{array}{|ccc|}12&4\\2&2\end{array}
$

2. Perform the operations as the problem suggests.

1. add the matrices inside the brackets.
2. multiply the result with the remaining LHS matrix.

Show your work to there, i will then help further.

3. Originally Posted by pickslides
Perform the operations as the problem suggests.

1. add the matrices inside the brackets.
2. multiply the result with the remaining LHS matrix.

Show your work to there, i will then help further.

$\begin{array}{|ccc|}x+0&2+1&-1+2\\0+0&y+0&w+2\end{array}
=
\begin{array}{|ccc|}x&3&1\\0&y&w+2\end{array}
$

x,3,1
0,y,w+2
*
1,1
3,z
4,2
=
x,9,1
0,2y,,2w,4

This is what i got....

4. Originally Posted by Anemori

x,3,1
0,y,w+2
*
1,1
3,z
4,2
=
x,9,1
0,2y,,2w,4

I get

$\left(\begin{array}{ccc}x&3&1\\0&y&w+2\end{array}\ right)
\times \left(\begin{array}{ccc}1&1\\3&z\\4&2\end{array}\r ight)
= \left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+ 2(w+2)\end{array}\right)$

Now solve

$
\left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+ 2(w+2)\end{array}\right) = \left(\begin{array}{cc}12&4\\2&2\end{array}\right)
$

Might need to do some expanding on the LHS first!

5. Originally Posted by pickslides
I get

$\left(\begin{array}{ccc}x&3&1\\0&y&w+2\end{array}\ right)
\times \left(\begin{array}{ccc}1&1\\3&z\\4&2\end{array}\r ight)
= \left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+ 2(w+2)\end{array}\right)$

Now solve

$
\left(\begin{array}{cc}x+9+4&x+3z+2\\3y+4(w+2)&yz+ 2(w+2)\end{array}\right) = \left(\begin{array}{cc}12&4\\2&2\end{array}\right)
$

Might need to do some expanding on the LHS first!

What do you mean expand? How do you do that?

6. Originally Posted by Anemori
What do you mean expand? How do you do that?
I mean the bottom terms in the LHS matrix.

I.e. $3y+4(w+2) = 3y+4w+8$

You then need to make 4 equations and solve them simultaneously.

Equate the term in each corresponding postition from each matrix.

Here's the first.

$x+9+4= 12$

7. Thanks .. i got it...