Đáp án:
$2/\dfrac{1}{9}$
$3/15$
$4/\dfrac{76}{45}$
$5/0$
Giải thích các bước giải:
$2/\left ( -1\dfrac{1}{2} \right )\left ( -1\dfrac{1}{3} \right )\left ( -1\dfrac{1}{4} \right )...\left ( -1\dfrac{1}{9} \right )\\=\dfrac{-1}{2}.\dfrac{-2}{3}.\dfrac{-3}{4}...\dfrac{-8}{9}=\dfrac{1}{9}\\3/\dfrac{5^{3}.9^{4}}{25.3^{7}}=\dfrac{5^{3}.3^{8}}{5^{2}.3^{7}}=5.3=15\\4/\dfrac{3^{15}.5^{5}+3^{12}.5^{7}}{3^{17}.5^{6}-3^{14}.5^{8}}\\=\dfrac{3^{12}.5^{5}(3^{3}+5^{2})}{3^{14}.5^{6}(3^{3}-5^{2})}\\=\dfrac{3^{3}+5^{2}}{3^{2}.5(3^{3}-5^{2})}\\=\dfrac{27+125}{9.5(27-25)}\\=\dfrac{152}{90}=\dfrac{76}{45}\\5/\dfrac{9^{4}.27^{3}}{81^{4}}-\dfrac{3^{11}.4^{5}}{6^{10}}\\=\dfrac{3^{8}.3^{9}}{3^{16}}-\dfrac{3^{11}.2^{10}}{3^{10}.2^{10}}\\=3-3=0$
