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: <br /> - (-5y) - y + 2(-2y) = 160<br /><br />2. **Simplify:** Combine like terms:<br /> - -5y - y - 4y = 160<br /> - -10y = 160<br /><br />3. **Solve for y:** Divide both sides by -10:<br /> - y = -16<br /><br />4. **Solve for x:** Substitute the value of y back into x/5 = y:<br /> - x/5 = -16<br /> - x = -80<br /><br />5. **Solve for z:** Substitute the value of y into -2y = z:<br /> - z = -2(-16)<br /> - z = 32<br /><br />**Solution:** x = -80, y = -16, z = 32 <br />