SOLUTION: I need your help please........... 1. If the matrices A and B are the same size and A+B=A, then: a. Each element of B is 1. b. Each element of B is 0. c. A-B=A. d. B=I, th

Algebra ->  Algebra  -> College  -> Linear Algebra -> SOLUTION: I need your help please........... 1. If the matrices A and B are the same size and A+B=A, then: a. Each element of B is 1. b. Each element of B is 0. c. A-B=A. d. B=I, th      Log On


   

Question 2893: I need your help please...........
1. If the matrices A and B are the same size and A+B=A, then:
a. Each element of B is 1.
b. Each element of B is 0.
c. A-B=A.
d. B=I, the identity matrix.
e. B and C
2. For the matrices C and D below, find the value of the missing element in D that makes the matrix product CD=[10].
C=[10 15 -2 5] D=[2 -3 5]...

Answer by khwang(438) About Me  (Show Source):
You can put this solution on YOUR website!
1. Like regular numbers A+B =A implies B = 0 (zero matrix)
2. Not quuite clear tome. C=[10 15 -2 5]
let D=[2 -3 5 x]...
Your CD may mean the dot product or CD^t(transpose)
= 10*2 + 15*(-3)+ (-2)* 5 + 5 x = 10
= -35 + 5x =10, so x = 9.