eigenvalue 3

Now
From Av=λv
(A-λI)v=0
(A-I)v=0
where A-I
-3 6...(1)
-2 4...(2)
Since you want to find the v
Using Guassian elimination
It can be change to
-1 2
-1 2
That is
-1 2
0 0
or
1 -2
0 0
Of course you can use any method to find v