Apply law of total resistance in parallel circuit
[tex]\\ \tt\hookrightarrow \dfrac{1}{R}=\dfrac{1}{R_1}+\dfrac{1}{R_2}[/tex]
[tex]\\ \tt\hookrightarrow \dfrac{1}{9+2J}=\dfrac{1}{3-5j}+\dfrac{1}{R_2}[/tex]
[tex]\\ \tt\hookrightarrow \dfrac{1}{R_2}=\dfrac{1}{9+2J}-\dfrac{1}{3-5J}[/tex]
[tex]\\ \tt\hookrightarrow \dfrac{1}{R_2}=\dfrac{3-5J-9-2J}{(9+2J)(3-5J)}[/tex]
[tex]\\ \tt\hookrightarrow R_2=\dfrac{(9+2J)(3-5J)}{-6-7J}[/tex]