Question 764732
x^2 + 2x - 48 = 0
x^2 + 2x.......-48
x^2 + 2x + (2/2)^2.....  - 48
(x + 1)^2.....  -1 - 48
(x + 1)^2 - 49
OR
x^2 + 2x + 48 = 0
x^2 + 2x.......+ 48
x^2 + 2x + (2/2)^2.....+ 48
(x + 1)^2.......-1 + 48
(x + 1)^2 + 47
If you add +1 to one side
you must balance it up 
with -1 to the other side.
Hope this helps.
:-)