Question

Tìm x

a)3/4 : x - 17/5 = 7/10

b) 2/7 + 5/7x =8/21

c)11/5 - 6/5 : x = 4/7

d) -3/4x + 3/4 =11/12

Answer 1

a. \(\dfrac{3}{4}\) : x - \(\dfrac{17}{5}\) = \(\dfrac{7}{10}\)

\(\dfrac{3}{4}\) : x = \(\dfrac{7}{10}\) + \(\dfrac{17}{5}\)

\(\dfrac{3}{4}\) : x = \(\dfrac{41}{10}\)

x = \(\dfrac{3}{4}\) : \(\dfrac{41}{10}\)

x = \(\dfrac{3}{4}\) . \(\dfrac{10}{41}\)

x = \(\dfrac{15}{82}\)

Vậy x = \(\dfrac{15}{82}\)

Answer 2

a, \(\dfrac{3}{4}:x-\dfrac{17}{5}=\dfrac{7}{10}\)

\(\Rightarrow\dfrac{3}{4}:x=\dfrac{7}{10}+\dfrac{17}{5}\)

\(\Rightarrow\dfrac{3}{4}:x=\dfrac{41}{10}\)

\(\Rightarrow x=\dfrac{3}{4}:\dfrac{41}{10}\)

\(\Rightarrow x=\dfrac{15}{82}\)

b, \(\dfrac{2}{7}+\dfrac{5}{7}x=\dfrac{8}{21}\)

\(\Rightarrow\dfrac{5}{7}x=\dfrac{8}{21}-\dfrac{2}{7}\)

\(\Rightarrow\dfrac{5}{7}x=\dfrac{2}{21}\)

\(\Rightarrow x=\dfrac{2}{21}:\dfrac{5}{7}\)

\(\Rightarrow x=\dfrac{2}{15}\)

c, \(\dfrac{11}{5}-\dfrac{6}{5}:x=\dfrac{4}{7}\)

\(\Rightarrow\dfrac{6}{5}:x=\dfrac{11}{5}-\dfrac{4}{7}\)

\(\Rightarrow\dfrac{6}{5}:x=\dfrac{57}{35}\)

\(\Rightarrow x=\dfrac{6}{5}:\dfrac{57}{35}\)

\(\Rightarrow x=\dfrac{14}{19}\)

d, \(\dfrac{-3}{4}x+\dfrac{3}{4}=\dfrac{11}{12}\)

\(\Rightarrow\dfrac{-3}{4}x=\dfrac{11}{12}-\dfrac{3}{4}\)

\(\Rightarrow\dfrac{-3}{4}x=\dfrac{1}{6}\)

\(\Rightarrow x=\dfrac{1}{6}:\dfrac{-3}{4}\)

\(\Rightarrow x=\dfrac{-2}{9}\)