The left hand side of the equation is almost a perfect square:
In order for it to be a perfect square:  x^2 + 4x + ____ = 2 + ____
To find the number that completes the square take 1/2 of 4 and square it
So 4 gets added to both sides
Then the right side becomes 6
Then we can write the left side like this: (x + 2) ^2
So (x + 2)^2 = 6
then take the sqrt of both sides but do not forget the +/- with the sqrt
Then subtract 2 from both sides:
You will have two answers a plus and a minus and you can check your work by using the quadratic formula 🙂