Question

Bài 1. Thực hiện phép tính:

k) \(-\sqrt{\dfrac{5^2}{4^3}}\) + ( \(\dfrac{1}{4}\) - \(\dfrac{1}{2}\) )³ + \(\left|\dfrac{-3}{7}\right|\) . \(\dfrac{7}{12}\)

n) \(\sqrt{64}\) + 2\(\sqrt{-3^2}\) - 7\(\sqrt{1,69}\) + 3\(\sqrt{\dfrac{25}{16}}\)

Answer 1

\(a,-\sqrt{\dfrac{5^2}{4^3}}+\left(\dfrac{1}{4}-\dfrac{1}{2}\right)^3+\left|\dfrac{-3}{7}\right|.\dfrac{7}{12}\)
\(=-\sqrt{\dfrac{25}{64}}+\left(\dfrac{1}{4}-\dfrac{2}{4}\right)^3+\dfrac{3}{7}.\dfrac{7}{12}\)
\(=-\dfrac{5}{8}+\left(\dfrac{-1}{4}\right)^3+\dfrac{1}{4}\)
\(=\dfrac{-5}{8}+\dfrac{-1}{64}+\dfrac{1}{4}\)
\(=\dfrac{-40}{64}-\dfrac{1}{64}+\dfrac{16}{64}\)
\(=\dfrac{-25}{64}\)
Sửa đề: \(b,\sqrt{64}+2\sqrt{3^2}-7\sqrt{1,69}+3\sqrt{\dfrac{25}{16}}\)
\(=8+2\sqrt{9}-7.1,3+3.\dfrac{5}{4}\)
\(=8+2.3-9,1+3,75\)
\(=8+6-9,1+3,75\)
\(=14-9,1+3,75\)
\(=4,9+3,75\)
\(=8,65\)