AC circuit

A resistance $(R)$ , inductance $(L)$ and capacitance $(C)$ are connected in series to an ac source of voltage $V$ having variable frequency. If the energy delivered by the source to the circuit during one period if the operating frequency is twice the resonance frequency is $E=\frac{πR\sqrt{LC}V^{2}}{R^{2}+x\left(\frac{L}{C}\right)}$
Find $x$ .