Energy Balance Equation

My question was question 3. The energy Balance Equation is used to calculate the average temperature of the Earth in Kelvins. First I solved it symbolically then with numbers.  S/4 (1-A)/εσ = εσTe^4/εσ  –> 1/4^[S/4εσ(1-A)] = [Te^4]^1/4  –>   [S/4εσ(1-A)]^1/4=TeS=Solar Constant=1370 w/m^2/k^4A=Albedo=3ε=Epsilon=1σ=sigma=5.67×10^-8 [(1370)(1-.3)/4(1)(5.67x10^-8)]^1/4 = Te  –>  Te = 255 Kelvins