\log (x^2  + y^2 ) = 1 + \log 13 = \log 10 + \log 13 = \log (10*13) \to x^2  + y^2  = 130 \\ 
 \log (x + y) = \log (x - y) + \log 2^3  = \log \left[ {(x - y)*2^3 } \right] \to x + y = 8(x - y) \\