Question

TINH: \(A=\left(\sqrt{9-\sqrt{56}}-\sqrt{15+2\sqrt{56}}\right)\div5\sqrt{2}\)

Answer 1

\(A=\left(\sqrt{9-\sqrt{56}}-\sqrt{15+2\sqrt{56}}\right)\div5\sqrt{2}\)

\(A=\left[\left(\sqrt{\left(\sqrt{7}-\sqrt{2}\right)^2}\right)-\left(\sqrt{\left(\sqrt{8}+\sqrt{7}\right)^2}\right)\right]\div5\sqrt{2}\)

\(A=\left(\left|\sqrt{7}-\sqrt{2}\right|-\left|\sqrt{8}+\sqrt{7}\right|\right)\div5\sqrt{2}\)

\(A=\left(\sqrt{7}-\sqrt{2}-\sqrt{8}-\sqrt{7}\right)\div5\sqrt{2}\)

\(A=\left(-\sqrt{10}\right)\div5\sqrt{2}\)

\(A=\frac{-\sqrt{5}}{5}\)