Since , and , all you need to do is see if . The proof will then be complete.

Disregard my previous answer...see Iso's post below...XD2.) LetAbe anMxNmatrix andBbe anNxPmatrix.

(a) How many multiplications are needed to calculateAB?

I'm not sure what is to be done here...(b) How many additions are needed to calculateAB?

Hint: the dimension of is 1 x 1 and the dimension of is 3 x 3.3.) Find(X)(X^T)and(X^T)(X), whereX= (1,-1,2).

Note: X^Tis the transpose ofX.

Any help would be very very very much appreciated. I'm so desperate!

Can you try to take it from here?