a/ \(x=\frac{1}{4}+\frac{2}{13}=\frac{13+8}{52}\)
\(\Rightarrow x=\frac{21}{52}\)
b/ \(\frac{x}{3}=\frac{2}{3}+-\frac{2}{7}\)
\(\Rightarrow\frac{x}{3}=\frac{8}{21}\Rightarrow21x=8.3=24\)
\(\Rightarrow x=\frac{24}{21}=\frac{8}{7}\)
giai
x = 1/4+2\13
x= 13/52+8/52
x=21/52
vay x=21/52
b x/3 = 2/3 +-2/7
x/3= 17/21 + -6/21
x/3 = 11/21
x/3= 11/21