I'm not sure exactly where I went wrong on this question. My professor put a 7.9v as the answer, but I can't seem to figure out how. please help

3. For the circuit shown below, find the power dissipated by R2. R. =20 Reg = 30+ 18 =0.063 0.5AWW R1=200 + 4 10V RZ=300 R3=500 0. 083 R4=201 M Ry: 20 0. 1 - = 1 + 1 = 6. 1 Reg 20 20 Rea= 0.1+ 0.053 10y 30.058 = 0.153.52 10V 0. 15351 I , = R . = 10v = 0.5 A 20 I , = V = 10v = 3052 = 0.33A Vy = 1R2 = (6. 33A )(30 ) = 9.9v