Question

Solve by completing the square x^2+2x-3=0

Answer 1

We can use
(x-1)(x+3) = 0

Therefore,
x = 1, x = -3

Answer 2

Or we can also do like this:
x^2 + 2x - 3=0
x^2 +2x + 1 -4=0(I just wrote 1-4 instead of -3)
(x+1)^2-4=0
(x+1)^2=4
\[(x+1)=\pm2\]
x=1 or x=-3