Yes, first we have to multiply every number in the first row by every number in the first column, add them and place it in the upper left-hand corner of the product.
-2 4 0 1 8 3
3 2 4 8 1 5
Maxine, do you know what the first step is with this example?
That's right. So, R1xC1 is (-2)(3) + (8)(4)= 26. We now put 26 in the upper-left corner of the result matrix.
My memory is still fresh! Let's see one of the students continue the problem!
Ok class, who wants to finish the rest of the first row?
Nobody? Come on guys, be enthusiastic, take a risk! Ok Jennifer, you answer this
I don't want to answer it, please ask someone else
Ok then. Jake! please come up to the board to solve this problem for the class.
Ok what do you do now?
Now you multiply the first row in the 3x2 by the second column in the 2x3. You get (-2)(2) + (4)(1) = 0. Then you multiply the first row by the third column. You get (-2)(4) + (4)(5) = 12
26 0 12
Great job Jake! You did that like it was 2+2! You can sit now.
Oh yea! I saw this when studying for my subject test!
R1xC2: -4+4=0 R1xC3: 20-8=12
Yaseen, are you late again? What was it this time, you slept too long?
Seems like we've got a late one haha.
I'm so sorry, I had a doctor's appointment, I just got back to school.
Since you're late, you'll finish the next row of this matrix multiplication example
Oof that'll be tough.
That's not good, I wasn't here for the beginning of the lesson.
Fill out the next row.
26 0 12
Hey Kamran, don't you think your being a little harsh?
Oh! I've seen this before, I think I can do it.
You're close and have the right idea, but that isn't it. It doesn't go by individual number, but rather multiplying a specific row with a specific column
26 0 12
I think I'm supposed to multiply each number in the left matrix by the numbers in each column in the right matrix and add them. So it would be (0)(3)+(0)(8) giving me zero for the result of the first number in the middle row?
26 0 12 8 1 5
So that means I would have to do (0x3)+(1x8), then (0x2)+(1x1) and lastly (0x4)+(1x5)?
R2xC1: 0+8=8 R2xC2: 0+1=1 R2xC3: 0+5=5
You saved yourself there Yaseen, now that your seated, I'll finish the last row since we're running out of time
26 0 12 8 1 5 48 19 47
R3xC1: 24+24=48 R3xC2: 16+3=19 R3xC3: 32+15=47
Class is almost over already? I guess time flies when you're having fun!
Ok class, let's thank Maxine for coming out and being such a wonderful addition to our class!