kill(all)$

fpprintprec:4;

van=facebook.com/LearningCalculus$

A:[
    x+y+x*y=250,
    y+z+y*z=216,
    x+z+z*x=300]$

X:[ x, y, z ]$

s:solve(A,X)$

float(s[1]);
float(s[2]);

radcan(sum(rhs(s[1][i]),i,1,3));float(%);
radcan(sum(rhs(s[2][i]),i,1,3));float(%);