How Va from first equation(5m/s) doesn't equal Va from last equation(4.36m/s)

You get the SAME answer from both equations:

Explanation:

Notice that you are dealing with vector equations, and that the first one doesn't give you 5 m/s for the magnitude.

You need to add V0 = 3 (in the x-direction), to

Therefore, the answer for VA from the first equation is:

which is exactly what was calculated in the second approach considering from point C.