Dăm factor comun pe x² :
[tex] {x}^{4} - 36 {x}^{2} = {x}^{2} \Big( {x}^{2} - 36 \Big) = {x}^{2} \Big( {x}^{2} - {6}^{2} \Big) = \\ [/tex]
[tex] = \boldsymbol {{x}^{2} \Big(x - 6\Big)\Big(x + 6\Big)} [/tex]
