1. Yes x^2 + 4x + 4 - 4 + 3 = 0 is still equivalent to x^2 + 4x + 3 = 0 since whilst we have added a 4 to the function, we have also subtracted a 4, and since +4 - 4 = 0, we haven't actually changed the value of the equation
2. -1 is the sum of -4 and 3
3. (x + 2)^2 - 1 = (x + 2 + sq.root of 1)(x + 2 - sq.root of 1)
= (x + 2 + 1)(x + 2 - 1)
= (x + 3)(x + 1)
(x + 3)(x + 1) = 0
x = -3 or x = -1
Hope that makes sense :)