a) \(\frac{1}{2}-\frac{1}{4}.\left(-\frac{6}{5}\right)\)

\(=\frac{1}{2}-\left(-\frac{3}{10}\right)\)

\(=\frac{4}{5}\)

b) \(\frac{\left(\frac{1}{9}\right)^0.3^2.9^3}{729}=\frac{1.9.729}{729}=\frac{9.729}{729}=9\)

=9

=9

Ta có: \(A=\left[6.\left(-\frac{1}{3}\right)^2-3.\left(-\frac{1}{3}\right)+1\right]:\left(\frac{-1}{3}-1\right)\)

\(=\left(6.\frac{1}{9}-\left(-1\right)+1\right):\left(\frac{-4}{3}\right)\)

\(=\left(\frac{2}{3}+2\right).\left(\frac{-3}{4}\right)\)

\(=\frac{8}{3}.\left(-\frac{3}{4}\right)\)

\(=-2\)

\(B=\left(729-1^3\right)\left(729-3^3\right)...\left(729-125^3\right)\)

\(\Rightarrow B=\left(729-1^3\right)\left(729-3^3\right)...\left(729-9^3\right)...\left(729-125^3\right)\)

\(\Rightarrow B=\left(729-1^3\right)\left(729-3^3\right)...0...\left(729-125^3\right)\)

\(\Rightarrow B=0\)

Vì -2 < 0 nên A < B

Vậy A < B

P/S : Good Luck
~Best Best~

a) \(\dfrac{1}{2}-\dfrac{3}{4}.\dfrac{-6}{5}\)

\(=\dfrac{1}{2}-\dfrac{3.\left(-6\right)}{4.5}\)

\(=\dfrac{1}{2}-\dfrac{-18}{20}\)

\(=\dfrac{1}{2}+\dfrac{9}{10}\)

\(=\dfrac{5}{10}+\dfrac{9}{10}\)

\(=\dfrac{5+9}{10}\)

\(=\dfrac{14}{10}\)

\(=\dfrac{7}{5}\)

b) \(\dfrac{\dfrac{1^0}{9}.3^2.9^3}{729}\)

\(=\dfrac{9^{-1}.3^2.9^3}{729}\)

\(=\dfrac{9^{-1}.9.9^3}{729}\)

\(=\dfrac{9^{-1+1+3}}{729}\)

\(=\dfrac{9^3}{729}\)

\(=\dfrac{729}{729}\)

\(=1\)