Determine the largest area of an isosceles triangle that is enclosed within a unit cube.
What is the answer if the triangle is equilateral?
If x, y, z satisfy:
x + y + z = 12,
1/x + 1/y + 1/z = 2, and
x3 + y3 + z3 = -480,
find x2y + xy2 + x2z + xz2 + y2z + yz2.