If 
3
1
A
1
2


= 

−

, show that A2 – 5A + 7I = 0 6 Find x, if [
]
1
0
2
5
1
0
2
1
4
O
2
0
3
1
x
x

  

  
−
−
=

  

  

  
7 A manufacturer produces three products x, y, z which he sells in two markets