In each of the Problems below, determine the critical point x = x⁰, and then classify its type and examine its stability by making the transformation x = x⁰ + u.

1. dx/ dt = [ 1 1 [ 2
x −
1 −1 ] 0 ]

2. dx/ dt = [ -2 1 [ -2
x −
1 −2 ] 1 ]

3. dx/ dt = [ -1 -1 [ -1
x −
2 −1 ] 5 ]

4. dx/ dt = [ 0 −β [ α
x − α, β, γ, δ > 0
δ 0 ] −γ ]