grade 11 math help?

Question

Solve using matrix notation:

a+b+c=26
b=3a
c=4a

if you could tell me how to do this showing the steps using matrix notation and not algebra thanks

Answer 1

Transform all your equations so that the variables are on the left and the constant is on the right:
a + b + c = 26
3a - b + 0c = 0
4a + 0b -c = 0
Form a matrix as in the pic:

http://s236.photobucket.com/albums/ff177/jsardi56/?action=view¤t=matrixsolution11-15-07.jpg