A flea jumps straight up to a maximum height of 0.550 m. what is its initial velocity v0 as it leaves the ground?

Since my givens are x =.550m [Vsub0] = unknown

[Asubx] = = 9.80

[Vsubx]^2 = [Vsub0x]^2 + 2[Asubx] * (X-[Xsub0]

[Vsubx]^2 = [Vsub0x]^2 + 2[Asubx] * (X-[Xsub0])

Vsubx is the final velocity, which at the max height is 0, and Xsub0 is just 0 as that's where it starts so I just plug the rest in

0^2 = [Vsub0x]^2 + 2[-9.80] * (.550)

0 = [Vsub0x]^2 - 10.78

10.78 = [Vsub0x]^2

Sqrt (10.78) = 3.28 m/s