Math question!! :O Help!

Question

anonymous · Answer

@TehAustin question from a practice quiz

anonymous · Answer

Same one?

anonymous · Answer

Oh lol well do you know how to do this kind of problem?

anonymous · Answer

click the link

anonymous · Answer

Ok@hartnn will you help me again?? lol sorry

anonymous · Answer

@hartnn

hartnn · Answer

have u learned matrix multiplication ?

anonymous · Answer

a little of it

hartnn · Answer

so can u multiply 2 matrices ??

anonymous · Answer

matrices are my weakness as you can see :/

hartnn · Answer

i believe u have choices here too.....else this will be very lengthy problem to solve....

anonymous · Answer

ok hold on

hartnn · Answer

1st element = 15

anonymous · Answer

There

anonymous · Answer

So the first answer?

hartnn · Answer

as u can see there is only 1 matrix with 1st element = 15
yes, first.

anonymous · Answer

@hartnn Thanks your a lot of help :)

hartnn · Answer

nopes, i would be more happy if u would have understood the method...

anonymous · Answer

explain it to me then

hartnn · Answer

|dw:1347303006293:dw|
matrix multiplication is performed as :
for 1st element u multiply corresponding elements of 1st row of 1st matrix and 1st column of 2nd matrix and then adding all of them., as shown.
so u had BA right ?
first row of B was 3,6,3
first column of A was -1,2,2
multiplying and adding, we get :
3*(-1)+6*2+3*2 = 15
thats how i got 15...
does this make some sense to u ??

anonymous · Answer

Yes this makes a lot of sense @hartnn I appreciate you explaining it to me!