\(A=\frac{-5x}{21}+\frac{-5y}{21}+\frac{-5z}{21}\)
biết x + y = -z
2. Tìm x biết:
\(\left(x-5\right)\cdot\frac{30}{100}=\frac{200x}{100}+5\)\(60\%x+0,4x+\frac{x}{3}=2\)\(1\frac{2}{5}+\left(\frac{\frac{2}{7}+\frac{2}{17}+\frac{2}{37}}{\frac{5}{7}+\frac{5}{17}+\frac{5}{37}}\right)\cdot x=\frac{16}{5}\)