Ok, so first you isolate y. You do this by adding 1 to each side, erasing the -1 and making the right side 49. Then you take the square root of both sides to get rid of the square on the y, leaving you with y= + or - 9. Then substitute + and - 9 into the equation to see if they work. -9 squared is 49-1 is 48, so that works, and 9 squared is 49-1 is 48, so they both work. This works because the square of a negative is a positive, or else -9 would not work. Hope this helps! :D
