Ta có:
1/3 x X + 2/5 x ( X-1) = 4
1/3 x X + 2/5 x X - 2/5 = 4
X x ( 1/3 + 2/5 ) - 2/5 = 4
X x 11/15 = 4 + 2/5
X x 11/15 = 22/5
X = 22/5 : 11/5
X = 2
k mình nha :)
Ta có: \(\frac{1}{3}\times x+\frac{2}{5}\times\left(x-1\right)=4\)
\(\Rightarrow\frac{1}{3}\times x+\frac{2}{5}\times x-\frac{2}{5}=4\)
\(\Rightarrow x\times\left(\frac{1}{3}+\frac{2}{5}\right)-\frac{2}{5}=4\)
\(\Rightarrow x\times\frac{11}{15}-\frac{2}{5}=4\)
\(\Rightarrow x\times\frac{11}{15}=4+\frac{2}{5}=\frac{22}{5}\)
\(\Rightarrow x=\frac{22}{5}:\frac{11}{15}=\frac{22}{5}\times\frac{15}{11}\)
\(\Rightarrow x=6\)
Vậy \(x=6\)
