6) (x)/(5)=y;-2y=z và -x-y+2z=160

1. **Substitute:** Since we know x/5 = y and -2y = z, substitute these into the third equation: - (-5y) - y + 2(-2y) = 1602. **Simplify:** Combine like terms: - -5y - y - 4y = 160 - -10y = 1603. **Solve for y:** Divide both sides by -10: - y = -164. **Solve for x:** Substitute the value of y back into x/5 = y: - x/5 = -16 - x = -805. **Solve for z:** Substitute the value of y into -2y = z: - z = -2(-16) - z = 32**Solution:** x = -80, y = -16, z = 32