Anonymous

Steve has given you the information to answer the question. You know by the difference of cubes formula that x^3 - y^3 = (x - y)(x^2 + xy + y^2). And Steve worked out the value of x^2 + xy + y^2. That is enough to answer the question.

Anonymous

1/(x+y) = 1/x + 1/y Multiply all terms by xy(x+y) xy = x(x+y) + y(x+y) x^2 +xy + y^2 = 0 where x=\=0, y =\=0, x =\= y The only integer solution is (0,0) which is forbidden because it would cause division by zero. Other answers are complex.

Anonymous

Where is z in your equation? And do you mean: (1 / x) + y or: 1 / (x + y) Please use parenthesis to be clear.