In this case, we have: X_L- X_C = 8 - 11 = -3 Ω

So Z = 4 - 3j Ω in rectangular form.

Now to express it in polar form:

Using calculator, we find r = 5 and θ = -36.87°.

[NOTE: We usually express the phase angle (when voltage lags the current) using a negative value, rather than the equivalent positive value 323.13°.]

So Z = 5 ∠ -36.87° Ω