Posted by Bersy on Saturday, January 26, 2013 at 5:14pm.
Find the matrix A such that
1 0
−1 3
A =
−1 −8
2 11
.
Hint: Let
A =
a b
c d
A=

Math  Damon, Saturday, January 26, 2013 at 6:24pm
 1 0   a b  1 8 
1 3   c d   2 11 
so
1 a + 0 c = 1 > a = 1
1 b + 0 d = 8 > b = 8
1 a + 3 c = 2
but a = 1
1 + 3 c = 2
c = 1/3
1 b + 3 d = 11
but b = 8
8 + 3 d = 11
3 d = 3
d = 1