Question

[Nga Trần]

tìm x biết

giúp mình với, mình cảm ơn

Answer 1

[Hquynh]

Giải :

\(m,x-25\%x=-\dfrac{1}{8}\\ \Leftrightarrow x-\dfrac{1}{4}x=-\dfrac{1}{8}\\ \Leftrightarrow x\left(1-\dfrac{1}{4}\right)=-\dfrac{1}{8}\\ \Leftrightarrow\left(\dfrac{4-1}{4}\right)x=-\dfrac{1}{8}\\ \Leftrightarrow\dfrac{3}{4}x=-\dfrac{1}{8}\\ \Leftrightarrow x=\left(-\dfrac{1}{8}\right):\dfrac{3}{4}\\ \Leftrightarrow x=-\dfrac{1}{6}\)

Vậy \(x=-\dfrac{1}{6}\)

\(h,\dfrac{x+1}{2}=\dfrac{-3}{-8}\\ \Leftrightarrow\dfrac{x+1}{2}=\dfrac{3}{8}\\ \Leftrightarrow8\left(x+1\right)=3.2\\ \Leftrightarrow8x+8=6\\ \Leftrightarrow8x=6-8\\ \Leftrightarrow8x=-2\\ \Leftrightarrow x=-\dfrac{2}{8}=-\dfrac{1}{4}\)

Vậy \(x=-\dfrac{1}{4}\)

\(d,\left(\dfrac{3}{15}x-x\right).\dfrac{1}{-3}=\dfrac{-2}{5}\\ \Leftrightarrow\left(\dfrac{3}{15}-1\right)x=\dfrac{-2}{5}:\dfrac{1}{-3}\\ \Leftrightarrow\dfrac{-4}{5}x=\dfrac{6}{5}\\ \Leftrightarrow x=\dfrac{6}{5}:\left(-\dfrac{4}{5}\right)\\ \Leftrightarrow x=-\dfrac{3}{2}\)

Vậy \(x=-\dfrac{3}{2}\)

Answer 2

[HT.Phong (9A5)]

m) \(x-25\%x=-\dfrac{1}{8}\)

\(\Leftrightarrow x-\dfrac{1}{4}x=-\dfrac{1}{8}\)

\(\Leftrightarrow\dfrac{3}{4}x=-\dfrac{1}{8}\)

\(\Leftrightarrow x=-\dfrac{1}{8}:\dfrac{3}{4}\)

\(\Leftrightarrow x=-\dfrac{1}{8}.\dfrac{4}{3}\)

\(\Leftrightarrow x=-\dfrac{4}{24}=-\dfrac{1}{6}\)