Question
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
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
Answers
mdan
this one seems difficult...plz help
Steve
You have an equation AX=B
where
A =
(1 2 -3)
(-2 -1 3)
(-4 4 -1)
and
B =
(-3)
(0)
(-12)
A<sup>-1</sup> = 1/3 times
(11 10 -3)
(14 13 -3)
(12 12 -3)
So, X = A<sup>-1</sup>B = (1,-2,0)
where
A =
(1 2 -3)
(-2 -1 3)
(-4 4 -1)
and
B =
(-3)
(0)
(-12)
A<sup>-1</sup> = 1/3 times
(11 10 -3)
(14 13 -3)
(12 12 -3)
So, X = A<sup>-1</sup>B = (1,-2,0)
mdan
fabulous