Question

[lưu trâm]

Thực hiện phép tính ( tính nhanh nếu có )

a)  \(\dfrac{-6}{35}\) : \(\dfrac{-54}{49}\) 

b) \(\dfrac{-5}{7}\) . \(\dfrac{2}{11}\) + \(\dfrac{-5}{7}\) . \(\dfrac{-9}{11}\) + 1\(\dfrac{5}{7}\)

c) ( \(\dfrac{1}{3}\)  + \(\dfrac{3}{4}\) + \(\dfrac{13}{12}\) ) : (  \(\dfrac{12}{23}\) + \(\dfrac{123}{234}\) + \(\dfrac{1234}{2345}\) )

giúp mk với ạ!!

Answer 1

[456]

\(a,\dfrac{-6}{35}:\dfrac{-54}{49}\)

\(=\dfrac{-6}{35}\times\dfrac{49}{-54}\)

\(=\dfrac{-1}{5}\times\dfrac{7}{-9}\)

\(=\dfrac{-7}{-45}=\dfrac{7}{45}\)

Answer 2

[456]

\(b,\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{11}+\dfrac{12}{7}\)

\(=\dfrac{-5}{7}.\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{12}{7}\)

\(=\dfrac{-5}{7}.1+\dfrac{12}{7}\)

\(=\dfrac{-5}{7}+\dfrac{12}{7}=1\)