Comments

• Substitute x^2 by say t. You then have a quadratic equation in t which tou can solve by the usual method. Then each t = x^2 will give rise to 2 values for x and you'll have 4 roots for the 4th degree equation, as it should be in the general case.

  in How do you factor x^4-8x^2+15? Comment by physicist June 2021
• Substitute x^2 by say t. You then have a quadratic equation in t which tou can solve by the usual method. Then each t = x^2 will give rise to 2 values for x and you'll have 4 roots for the 4th degree equation, as it should be in the general case.

  in How do you factor x^4-8x^2+15? Comment by physicist June 2021
• kg is a unit of mass and litres a unit of volume. You cannot convert between different units!

  in Convert 15kg into litres? Comment by physicist June 2021
• kg is a unit of mass and litres a unit of volume. You cannot convert between different units!

  in Convert 15kg into litres? Comment by physicist June 2021
• kg is a unit of mass and litres a unit of volume. You cannot convert between different units!

  in Convert 15kg into litres? Comment by physicist May 2021