Question

I.Rút gọn rồi quy đồng mẫu các phân số sau

a, \(\dfrac{25.9-25.17}{\left(-8\right).80-8.10}\) ; \(\dfrac{48.12-48.15}{\left(-3\right).270-3.30}\) VÀ \(\dfrac{2^5.3}{600}\)

B, \(\dfrac{2^5.7+25}{25.5^2-2^5.3}\) VÀ\(\dfrac{3^4.5-3^6}{3^4.13+3^4}\)

Answer 1

a: \(\dfrac{25\cdot9-25\cdot17}{-8\cdot80-8\cdot10}=\dfrac{25\cdot\left(-8\right)}{\left(-8\right)\cdot\left(80+10\right)}=\dfrac{25}{90}=\dfrac{5}{18}=\dfrac{250}{900}\)

\(\dfrac{48\cdot12-48\cdot15}{\left(-3\right)\cdot\left(270+30\right)}=\dfrac{48}{300}=\dfrac{8}{50}=\dfrac{144}{900}\)

\(\dfrac{2^5\cdot3}{600}=\dfrac{96}{600}=\dfrac{144}{900}\)

b: \(\dfrac{2^5\cdot7+25}{25\cdot5^2-2^5\cdot3}=\dfrac{32\cdot7+25}{25\cdot25-32\cdot3}=\dfrac{249}{529}=\dfrac{1743}{7\cdot529}\)

\(\dfrac{3^4\cdot5-3^6}{3^4\cdot13+3^4}=\dfrac{3^4\left(5-9\right)}{3^4\left(13+1\right)}=\dfrac{-4}{14}=\dfrac{-2}{7}=\dfrac{-1058}{7\cdot529}\)

Answer 2