Demonstrate that each of the following NLPs is a posynomial geometric program by placing the model in standard form and detailing the sets Ki, and associated coefficients dk and ak,j.

(a) min 13x1x2>x3 + 91x1x3 s.t. 3x1 + 8x2 … x3 20> 1x324 … 4 x1, x2, x3 7 0

(b) min 40>x1 + x2>1x3 s.t. x1x2 … 1x322 18x1 + 14x2 … 2 x1, x2, x3 7 0