Question

Tính bằng cách hợp lý

A.[ 8/9 - 5/6] x 9/4

b.[6/5 + 12/25] + 13/25

c.[7/9 x 28/25] x 15/14

giúp mình đi mình tick cho

Answer 1

a: \(=\dfrac{48-45}{54}\cdot\dfrac{9}{4}=\dfrac{3}{54}\cdot\dfrac{9}{4}=\dfrac{27}{216}=\dfrac{1}{8}\)

b: \(=\dfrac{6}{5}+1=\dfrac{11}{5}\)

c: \(=\dfrac{7\cdot28\cdot15}{9\cdot25\cdot14}=\dfrac{1}{2}\cdot\dfrac{28}{25}\cdot\dfrac{5}{3}=\dfrac{140}{150}=\dfrac{14}{15}\)