x = 5,545454...
X= \(\frac{54}{99}\)
y = 2,121212 = \(\frac{12}{99}\)
Tổng là : \(\frac{54}{99}+\frac{12}{99}=\frac{2}{3}\)
k nha
x+y=5,545454...+2,121212...
x+y=7,666666...
\(x=5,545454...=5\left(54\right)=5+\frac{54}{99}=\frac{61}{11}\)
\(y=2,121212=2\left(12\right)=2+\frac{12}{99}=\frac{70}{33}\)
\(\Rightarrow x+y=\frac{61}{11}+\frac{70}{33}=\frac{23}{3}\)