Question

tìm x biết :

\(a,\frac{1}{2}-\frac{2}{3}x=\frac{7}{12}\) b,/x+\(\frac{1}{2}\)/=\(\frac{3}{4}\)

Answer 1

a/ \(\frac{1}{2}-\frac{2}{3}x=\frac{7}{12}\)

\(\Rightarrow\frac{2}{3}x=\frac{1}{2}-\frac{7}{12}=\frac{6}{12}-\frac{7}{12}=-\frac{1}{12}\)

\(\Rightarrow x=-\frac{1}{12}:\frac{2}{3}=-\frac{1}{12}.\frac{3}{2}=-\frac{3}{24}=-\frac{1}{8}\)

b/ \(\left|x+\frac{1}{2}\right|=\frac{3}{4}\)

\(\Rightarrow\left[{}\begin{matrix}x+\frac{1}{2}=\frac{3}{4}\\x+\frac{1}{2}=-\frac{3}{4}\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=\frac{3}{4}-\frac{1}{2}=\frac{3}{4}-\frac{2}{4}=\frac{1}{4}\\x=-\frac{3}{4}-\frac{1}{2}=\left(-\frac{3}{4}\right)+\left(-\frac{2}{4}\right)=-\frac{5}{4}\end{matrix}\right.\)

Answer 2

a, \(\frac{1}{2}-\frac{2}{3}x=\frac{7}{12}\)

=>\(\frac{2}{3}x=\frac{1}{2}-\frac{7}{12}\)

=>\(\frac{2}{3}x=-\frac{1}{12}\)

=>\(x=-\frac{1}{12}:\frac{2}{3}\)

=>\(x=-\frac{1}{12}.\frac{3}{2}\)

=>\(x=-\frac{1}{8}\)

b,/ \(x+\frac{1}{2}\)/ = \(\frac{3}{4}\)

=> \(\left[{}\begin{matrix}x+\frac{1}{2}=\frac{3}{4}\\x+\frac{1}{2}=-\frac{3}{4}\end{matrix}\right.=>\left[{}\begin{matrix}x=\frac{3}{4}-\frac{1}{2}\\x=-\frac{3}{4}-\frac{1}{2}\end{matrix}\right.=>\left[{}\begin{matrix}x=\frac{1}{4}\\x=-\frac{5}{4}\end{matrix}\right.\)

Answer 3

\(a,\frac{1}{2}-\frac{2}{3}x=\frac{7}{12}\)

\(\frac{2}{3}x=\frac{1}{2}-\frac{7}{12}=\frac{-1}{12}\)

\(x=\frac{-1}{12}:\frac{2}{3}=\frac{-1}{8}\)