Q:

Factor the expression:-\lambda ^{3}+4\lambda ^{2}+4\lambda -16

Accepted Solution

A:
Answer:[tex] -(\lambda -4)(\lambda -2)(\lambda +2) [/tex]Step-by-step explanation:What we want to fator is:[tex] -\lambda^3 + 4 \lambda^2 + 4\lambda - 16[/tex]There is no common factor, but let's factor it by grouping. The first two addends can be factor as follows:[tex]-\lambda^3 + 4 \lambda^2 = \lambda^2(-\lambda + 4) = -\lambda^2(\lambda - 4)[/tex]the second addends can be factor as well:[tex]4\lambda - 16 = 4(\lambda- 4)[/tex].Then our original expression can be rewritten like [tex]-\lambda^3 + 4 \lambda^2 + 4\lambda -16=\lambda^2(\lambda - 4) + 4(\lambda - 4)[/tex]And here the [tex](\lambda-4)[/tex] is the common factor![tex] -\lambda^2(\lambda - 4) + 4(\lambda - 4) = (\lambda - 4)(-\lambda^2 + 4)[/tex]Finally, we can factor the quadratic expression as a difference of squares [tex] -\lambda^2 + 4 = 4 - \lambda^2 = (2+\lambda)(2-\lambda)[/tex]Ant we get [tex](\lambda - 4)(-\lambda^2 + 4)= (\lambda - 4)(\lambda + 2)(2-\lambda)[/tex]now, we can extract the negative sign from [tex](2-\lambda)[/tex], and we get [tex] -(\lambda -4)(\lambda -2)(\lambda +2) [/tex].