a) \(\dfrac{2}{36}=\dfrac{1}{18}\)

\(\dfrac{8}{12}=\dfrac{2}{3}\)

b) \(\dfrac{10}{25}=\dfrac{2}{5}\)

\(\dfrac{14}{40}=\dfrac{7}{20}\)

a: \(\dfrac{5}{6}\cdot7=\dfrac{5\cdot7}{6}=\dfrac{35}{6}\)

b: \(\dfrac{7}{10}\cdot3=\dfrac{7\cdot3}{10}=\dfrac{21}{10}\)

c: \(5\cdot\dfrac{4}{21}=\dfrac{5\cdot4}{21}=\dfrac{20}{21}\)

d: \(2\cdot\dfrac{5}{9}=\dfrac{2\cdot5}{9}=\dfrac{10}{9}\)

a) = \(\dfrac{12}{17}\)

b) = \(\dfrac{31}{37}\)

a) \(\dfrac{3}{5}=\dfrac{21}{35};\dfrac{4}{7}=\dfrac{20}{35}\)

b) \(\dfrac{5}{6}=\dfrac{45}{54};\dfrac{7}{9}=\dfrac{42}{54}\)

a) \(\dfrac{2}{5}=\dfrac{2\times3}{5\times3}=\dfrac{6}{15}=\dfrac{2}{5}\)

\(\dfrac{4}{7}=\dfrac{4\times2}{7\times2}=\dfrac{8}{14}=\dfrac{4}{7}\)

\(\dfrac{13}{54}=\dfrac{13\times3}{54\times3}=\dfrac{39}{162}=\dfrac{13}{54}\) 

b) \(\dfrac{8}{20}=\dfrac{8:4}{20:4}=\dfrac{2}{5}\)

\(\dfrac{10}{16}=\dfrac{10:2}{16:2}=\dfrac{5}{8}\)

\(\dfrac{25}{65}=\dfrac{25:5}{65:5}=\dfrac{5}{13}\)

a) \(3\times\dfrac{4}{11}=\dfrac{3\times4}{11}=\dfrac{12}{11}\)

b) \(1\times\dfrac{5}{4}=\dfrac{1\times5}{4}=\dfrac{5}{4}\)

c) \(0\times\dfrac{2}{5}=\dfrac{0\times2}{5}=\dfrac{0}{5}=0\)

a: \(=\dfrac{3\cdot4}{11}=\dfrac{12}{11}\)

b: \(=\dfrac{1\cdot5}{4}=\dfrac{5}{4}\)

c: \(=\dfrac{0\cdot2}{5}=0\)

a, \(4\times\left(-\dfrac{1}{2}\right)^3-2\times\left(-\dfrac{1}{2}\right)^2+3\times\left(-\dfrac{1}{2}\right)+1\)

\(=\left(-\dfrac{1}{2}\right)\left[\left(4\times-\dfrac{1}{2}\right)-\left(2\times-\dfrac{1}{2}\right)+3\right]+1\)

\(=\left(-\dfrac{1}{2}\right)\left(-2+1+3\right)+1\)

\(=\left(-\dfrac{1}{2}\right)2+1\)

\(=-1+1\)

\(=0\)

@Trịnh Thị Thảo Nhi

a,