Solve x2 + 4x + 3 = 0 by completing the square.
-6, -1
-3, -1
1, 3
-6, -2

Sakura is not useless.

She is very useful to the plot, although she’s annoying sometimes I wouldn’t deem her useless. Especially in the second show we’re she is trained and becomes an amazing medical ninja. She’s also part of the reason kaguya was defeated