Bài 2:
a: \(x-\frac23=\frac{7}{12}\)
=>\(x=\frac{7}{12}+\frac23=\frac{7}{12}+\frac{8}{12}=\frac{15}{12}=\frac54\)
b: \(\frac12x+\frac18x=\frac34\)
=>\(\frac48x+\frac18x=\frac34\)
=>\(\frac58x=\frac34\)
=>\(x=\frac34:\frac58=\frac34\cdot\frac85=\frac{3\cdot2}{5}=\frac65\)
c: \(\left|x-\frac12\right|=\frac{15}{4}\)
=>\(\left[\begin{array}{l}x-\frac12=\frac{15}{4}\\ x-\frac12=-\frac{15}{4}\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac{15}{4}+\frac12=\frac{17}{4}\\ x=-\frac{15}{4}+\frac12=-\frac{13}{4}\end{array}\right.\)
Bài 1:
a: \(-\frac14+\frac27-\frac{5}{28}\)
\(=-\frac{7}{28}+\frac{8}{28}-\frac{5}{28}=\frac{1-5}{28}=-\frac{4}{28}=-\frac17\)
b: \(75\%-1\frac12+0,5:\frac{5}{12}\)
\(=\frac34-\frac32+\frac12\cdot\frac{12}{5}=\frac{-3}{4}+\frac65=\frac{-15+24}{20}=\frac{9}{20}\)
c: \(-\frac{7}{12}\cdot\frac38+\frac{-7}{12}\cdot\frac58+1\frac{7}{12}\)
\(=-\frac{7}{12}\left(\frac38+\frac58\right)+1+\frac{7}{12}\)
\(=-\frac{7}{12}+1+\frac{7}{12}=1\)
