a: =6/35x39/54=13/105

b: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{12}{7}=\dfrac{-5}{7}+\dfrac{12}{7}=1\)

Sửa đề: \(\left(\dfrac{1}{3}+\dfrac{3}{4}-\dfrac{13}{12}\right):\left(\dfrac{12}{23}+\dfrac{123}{234}+\dfrac{1234}{2345}\right)\)

\(=\left(\dfrac{4+9-13}{12}\right):\left(\dfrac{12}{23}+\dfrac{123}{234}+\dfrac{1234}{2345}\right)\)

=0

=1274.41176471

1274,4118

mk tính dư

1234567 - 1234560 + 3 + 234 - 567 + 1234 - 754 = 157

tk mk nha

\(\frac{3^8.5^9+15^8.3^2}{15^9.3^3-3^8.5^9}\)

\(=\frac{3^8.5^9+5^8.3^{10}}{5^9.3^{12}-3^8.5^9}\)

\(=\frac{3^8.5^8.\left(5+3^2\right)}{5^9.3^8.\left(3^4-1\right)}=\frac{14}{80}=\frac{7}{40}\)

\(=\frac{15^8.5+15^8.3^2}{15^8.5.3.3^3-15^8.5}\)

\(=\frac{15^8\left(5+9\right)}{15^8\left(5.3^4-5\right)}\)

\(=\frac{15^8.14}{15^8.400}\)

\(=\frac{14}{400}\)

\(=\frac{7}{200}\)

\(\frac{3^8\cdot5+15^8\cdot3^2}{15^9\cdot3^3-3^8\cdot5^9}\)

\(=\frac{3^8\cdot5^9+5^8\cdot3^9}{5^9\cdot3^3-3^8\cdot5^9}\)

\(=\frac{3^8\cdot5^8\left(5+3^2\right)}{5^9\cdot3^8\cdot\left(3^4-1\right)}\)

\(=\frac{14}{80}=\frac{7}{40}\)