Question

help meeeeeeee

Answer 1

a: \(=4\sqrt{7}+6\sqrt{7}-15\sqrt{7}+4\sqrt{7}-2\sqrt{5}\)

\(=-\sqrt{7}-2\sqrt{5}\)

b: \(=\dfrac{\sqrt{4+2\sqrt{3}}+\sqrt{4-2\sqrt{3}}}{\sqrt{2}}\)

\(=\dfrac{\sqrt{3}+1+\sqrt{3}-1}{\sqrt{2}}=\dfrac{2\sqrt{3}}{\sqrt{2}}=\sqrt{6}\)

c: \(=\dfrac{1}{2-\sqrt{3}+1}-\dfrac{1}{2+\sqrt{3}-1}\)

\(=\dfrac{1}{3-\sqrt{3}}-\dfrac{1}{\sqrt{3}+1}\)

\(=\dfrac{\sqrt{3}+1-3+\sqrt{3}}{2\sqrt{3}}=\dfrac{-2+2\sqrt{3}}{2\sqrt{3}}=\dfrac{\sqrt{3}-1}{\sqrt{3}}\)