60%x + 2/3x +x=680
x(3/5+2/3+1)=680
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60%x+2/3x+x=680
=> 0,6x+2/3x+x=680
=> x.(0,6+2/3+1)=680
=> x.34/15 =680
=> x =680:34/15
=> x =300
k mik nhé 
Vuthimailoan
\(60\%x+\frac{2}{3}x+x=680\)
\(\frac{3}{5}x+\frac{2}{3}x+x=680\)
\(x\left(\frac{3}{5}+\frac{2}{3}+1\right)=680\)
\(\frac{34}{15}x=680\)
\(x=300\)
Vậy x = 300
\(60\%x+\frac{2}{3}x+x=680\)
\(\Rightarrow\frac{3}{5}x+\frac{2}{3}x+x=680\)
\(\Rightarrow x\left(\frac{3}{5}+\frac{2}{3}+1\right)=680\)
\(\Rightarrow x\cdot\frac{34}{15}=680\)
\(\Rightarrow x=680\div\frac{34}{15}\)
\(\Rightarrow x=300\)
