1. The problem statement, all variables and given/known data show that: ( a - b ) x (a + b ) = 2a x b and wat is its geometric interpretation ?? I'm not sure what's wrong, but i somehow got the value as 2a and not wat was required... PLease help. 2. Relevant equations Since this is a proof, the answer i've arrived at is wrong. How do I arrive at the solution ? 3. The attempt at a solution First of all, i took the cross product and tried proving the statement, but couls arrive at it whatsoever. I ended up with a 2a actually. As for the second part, with the parallelogram idea, i really could not figure out how to find 2a x b. After analysis, I arrived at 2a , but am stuck there . please help.