Question

2. Tìm x, biết

a) \(\dfrac{-1}{4}\)-\(\dfrac{3}{4}\):x =\(\dfrac{-11}{36}\)

b) \(70\): \(\dfrac{4x+720}{x}\)=\(\dfrac{1}{2}\)

Giúp mình với

Answer 1

a, \(-\dfrac{1}{4}-\dfrac{3}{4}:x=-\dfrac{11}{36}\)

\(\Rightarrow\dfrac{3}{4}:x=-\dfrac{1}{4}-\left(-\dfrac{11}{36}\right)=\dfrac{1}{18}\)

\(\Rightarrow x=\dfrac{3}{4}:\dfrac{1}{18}=\dfrac{27}{2}\)

b, \(70:\dfrac{4x+720}{x}=\dfrac{1}{2}\)

\(\Rightarrow\dfrac{4x+720}{x}=140\)

\(\Rightarrow4x+720=140x\Rightarrow140x-4x=720\)

\(\Rightarrow136x=720\Rightarrow x=\dfrac{90}{17}\)

Chúc bạn học tốt!!!

Answer 2

a)\(\dfrac{-1}{4}-\dfrac{3}{4}:x=\dfrac{-11}{36}\)

\(\dfrac{3}{4}:x=\dfrac{-1}{4}-\left(\dfrac{-11}{36}\right)=\dfrac{1}{18}\)

\(\Rightarrow x=\dfrac{3}{4}:\dfrac{1}{18}=\dfrac{27}{2}\)

b)\(70:\dfrac{4x+720}{x}=\dfrac{1}{2}\)

\(\dfrac{4x+720}{x}=70:\dfrac{1}{2}=140\)

\(\Rightarrow4x+720=140x\)

\(\Rightarrow140x-4x=720\)

\(\Rightarrow136x=720\)

\(\Rightarrow x=\dfrac{90}{17}\)