PLS I NEED YOUR HELP!!!!!!!

Answer:
[tex] R_2 = \dfrac{R_1R_T}{R_1 - R_T} [/tex]
Step-by-step explanation:
[tex] R_T = \dfrac{R_1R_2}{R_1 + R_2} [/tex]
[tex] (R_1 + R_2)R_T = R_1R_2 [/tex]
[tex] R_1R_T + R_2R_T = R_1R_2 [/tex]
[tex] R_2R_T - R_1R_2 = -R_1R_T [/tex]
[tex] R_2(R_T - R_1) = -R_1R_T [/tex]
[tex] R_2 = \dfrac{-R_1R_T}{R_T - R_1} [/tex]
[tex] R_2 = \dfrac{R_1R_T}{R_1 - R_T} [/tex]