1. ## Matrices

Im trying to evaluate the following, but not sure if i'm going wrong,could someone please check this.

Evaluating 2A + 3B

Where

$A = \left(\begin{array}{cc}3&7\\4&-1\\-5&2\end{array}\right)$ $B = \left(\begin{array}{cc}-5&-3\\10&6\end{array}\right)$

To evaluate i use the scalar multiplication?

so:

2A becomes = $\left(\begin{array}{cc}6&14\\8&-2\\-10&4\end{array}\right)$

and

3B becomes= $\left(\begin{array}{cc}-15&9\\30&18\end{array}\right)$

So my dillema is, i cant add these together can i because the incorrect rows to columns - or am i thinking this through to much?

Im trying to evaluate the following, but not sure if i'm going wrong,could someone please check this.

Evaluating 2A + 3B

Where

$A = \left(\begin{array}{cc}3&7\\4&-1\\-5&2\end{array}\right)$ $B = \left(\begin{array}{cc}-5&-3\\10&6\end{array}\right)$

To evaluate i use the scalar multiplication?

so:

2A becomes = $\left(\begin{array}{cc}6&14\\8&-2\\-10&4\end{array}\right)$

and

3B becomes= $\left(\begin{array}{cc}-15&9\\30&18\end{array}\right)$

So my dillema is, i cant add these together can i because the incorrect rows to columns - or am i thinking this through to much?

No, your thinking is just fine. You cannot add matrices with different dimensions.

3. Thanks Masters, so is that evaluated as far as possible?

Thanks Masters, so is that evaluated as far as possible?
That would be correct.