If you write this as
AX = B
then
X = A-1B
A-1 =
(1 1)
(1 2)
now just crank it out.
Given:
|4 -2| X = 2|-4 -4|
|-1 1| | 2 2|
What is X?
I solved this and couldn't get an answer - that is, the result was undefined/null, as it didn't like how the multiplication worked. I got this for every way I tried doing it, including by transposing the matrices and solving as per usual solve equation.
Is it actually just an equation with no answer, or am I missing something?
3 answers
oops - misspoke:
A-1 =
1/2 (1 2)
(1 4)
So, X =
(0 0)
(4 4)
see
http://www.wolframalpha.com/input/?i=(inverse+%7B%7B4,-2%7D,%7B-1,1%7D%7D)*(2%7B%7B-4,-4%7D,%7B2,2%7D%7D)
A-1 =
1/2 (1 2)
(1 4)
So, X =
(0 0)
(4 4)
see
http://www.wolframalpha.com/input/?i=(inverse+%7B%7B4,-2%7D,%7B-1,1%7D%7D)*(2%7B%7B-4,-4%7D,%7B2,2%7D%7D)
Oooh, I forgot about inverse matrices. Thank you!