Posted by
mdan on
.
Write the system as a matrix equation and solve using inverses.
x1 + 2x2  x3 = 3
2x1  x2 + 3x3 = 0
4x1 + 4x2  x3 = 12
A. x1 = 2, x2 = 3, x3 = 1
B. x1 = 1, x2 = 2, x3 = 1
C. x1 = 1, x2 = 2, x3 = 0
D. x1 = 1, x2 = 3, x3 = 1

maths 
mdan,
this one seems difficult...plz help

maths 
Steve,
You have an equation AX=B
where
A =
(1 2 3)
(2 1 3)
(4 4 1)
and
B =
(3)
(0)
(12)
A^{1} = 1/3 times
(11 10 3)
(14 13 3)
(12 12 3)
So, X = A^{1}B = (1,2,0)

maths 
mdan,
fabulous