+0

Confused

0
167
3
+1690

tried figuring it out myself ,but I am confused

Oct 2, 2019
edited by jjennylove  Oct 3, 2019

#1
+6179
0

can you multiply two matrices together?

The top question wants you to multiply A times B, drag that to the box, then multiply that by C, and drag that product to the box.

The bottom question wants you to multiply B times C first, drag that into the box, then multiply A times that and put it in the box.

Oct 3, 2019
#2
+109450
+1

First one :

AB   =

[7 1 ]  *   [ 1 -2 5  ]  =  [ 7*1  + 1*2     7*-2 + 1*4      7*5 + 1*1 ]   =   [ 9  -10  36 ]

[3 1 ]       [2  4  1 ]       [ 3*1 + 1*2 +   3*-2 + 1*4      3*5 + 1*1 ]        [ 5   -2   16]

(AB)C  =

[ 9  -10  36 ]   *   [ 2 ]   =   [ 9*2 +  -10 * -1  + 36 * 0]  =     [  28   ]

[ 5  -2   16]          -1           [ 5*2 +   -2*-1  +   16 * 0 ]        [  12   ]

[ 0 ]

And

BC  = [1  -2  5  ] *  [ 2 ]  =   [ 1*2  +  -2*-1   + 5*0 ]   =    [ 4 ]

[ 2  4  1  ]      -1         [  2*2 +   4*-1  +  1*0 ]          [ 0 ]

[ 0 ]

A(BC) =  [7 1]  *   [ 4 ]  =   [ 7*4  + 1 * 0 ]  =    [ 28  ]

[3 1]      [ 0]       [ 3*4 +   1 * 0 ]        [  12 ]

Oct 3, 2019
#3
+109450
+1

The second one is correct  !!!!

Oct 3, 2019