kill(all);

van=facebook.com/LearningCalculus$

f(x,y):=(x+y)^3+(x-y)^3 - 64;

g(x,y):=(4*x/y)*(x^2+3*y^2) - 64;

is(f(2,2) = g(2,2));

is(f(-2,-2) = g(-2,-2));