Question

rút gọn biểu thức

D=\(\sqrt{a^2-10a+25}+\sqrt{a^2-6a+9}\left(3< =a< =5\right)\)

Answer 1

Ta có: \(D=\sqrt{a^2-10a+25}+\sqrt{a^2-6a+9}\)

\(=\sqrt{\left(a-5\right)^2}+\sqrt{\left(a-3\right)^2}\)

\(=\left|a-5\right|+\left|a-3\right|\)

\(=5-a+a-3\)(Vì \(3\le a\le5\))

=2