b) Ta có \(x:3=y:4.\)
\(\Rightarrow\frac{x}{3}=\frac{y}{4}\)
\(\Rightarrow\frac{3x}{9}=\frac{2y}{8}\) và \(3x+2y=2.\)
Áp dụng tính chất dãy tỉ số bằng nhau ta được:
\(\frac{3x}{9}=\frac{2y}{8}=\frac{3x+2y}{9+8}=\frac{2}{17}.\)
\(\Rightarrow\left\{{}\begin{matrix}\frac{x}{3}=\frac{2}{17}\Rightarrow x=\frac{2}{17}.3=\frac{6}{17}\\\frac{y}{4}=\frac{2}{17}\Rightarrow y=\frac{2}{17}.4=\frac{8}{17}\end{matrix}\right.\)
Vậy \(\left(x;y\right)=\left(\frac{6}{17};\frac{8}{17}\right).\)
Chúc bạn học tốt!
a, \(\left(2x-1\right)^2=\frac{1}{4}\)
\(\Rightarrow\left(2x-1\right)^2=\left(\frac{1}{2}\right)^2\)
\(\Rightarrow2x-1=\frac{1}{2}\)
\(\Rightarrow2x=\frac{1}{2}+1\)
\(\Rightarrow2x=\frac{3}{2}\)
\(\Rightarrow x=\frac{3}{2}:2\)
\(\Rightarrow x=\frac{3}{4}\)
c, \(\left(x-\frac{1}{2}\right)^3=\left(\frac{1}{3}\right)^3\)
\(\Rightarrow x-\frac{1}{2}=\frac{1}{3}\)
\(\Rightarrow x=\frac{5}{6}\)
