mateusy
Hello! I am wondering if I am missing something here at the end? So the result is 4, but how was it connected back to the answer being -2?
I guess you square root the result to get back to the original expression? But how do we get sqrt(4)=-2?
For some reason the last part of the solution was missing there:
Since the square of the expression is 4, the expression itself must be either 2 or -2. However, since the product of two positive terms and one negative term is negative (\((\sqrt{4-\sqrt{15}})(4 + \sqrt{15})(\sqrt{6} - \sqrt{10})=positive*positive*negative=negative\)), we know that \((\sqrt{4-\sqrt{15}})(4 + \sqrt{15})(\sqrt{6} - \sqrt{10})\) is negative. Therefore, the final answer is -2.
The post with the solution is updated.