# help solving a matrix equation

• Oct 10th 2012, 11:02 AM
jepherz
help solving a matrix equation
[a-b b+a
3d+c 2d-c] = [8 1; 7 6]

Sorry I don't know how to format the matrix. No steps taken yet, I have no idea how to proceed... have to find a, b, c ,d.
• Oct 10th 2012, 11:06 AM
HallsofIvy
Re: help solving a matrix equation
$\begin{bmatrix}a- b & b+ a \\ 3d+ c & 2d- c\end{bmatrix}= \begin{bmatrix}8 & 1 \\ 7 & 6\end{bmatrix}$

Do you at least know what it means to say that two matrices are equal? It means that corresponding entries are equal:
a- b= 8, b+ a= 1, 3d+ c= 7, 2d- c= 6.

Solve the first two equations for a and b, the last two for c and d.
• Oct 10th 2012, 11:23 AM
jepherz
Re: help solving a matrix equation
I know what it means... >< So far we've only done (reduced) row echelon form and got into multiplying matrices, this is the first time we've seen integers/equations in the matrix like a-b and also a 2 column matrix on the right. Still don't know how to solve this...
• Oct 10th 2012, 12:06 PM
jepherz
Re: help solving a matrix equation
nevermind, I figured it out with basic algebra =/ Sorry, I'm just getting back into college after some years off and my last math class was about 5 years ago...