SOLUTION: Factor by grouping, if possible, and check. w3 + 7w2 + 4w + 28

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Question 384143: Factor by grouping, if possible, and check.

w3 + 7w2 + 4w + 28
Answer by Jk22(389) About Me  (Show Source):
You can put this solution on YOUR website!
w3 + 7w2 + 4w + 28

group w3 and 4w : times 4/w^2
group 7w2, 28 : times 4/w^2

hence (w3+4w)+(7w2+28)=w(w^2+4)+7(w^2+4)=(w+7)(w^2+4)

w^2+4 is not factorisable on R.

Check : (w+7)(w^2+4)=w^3+4w+7w^2+28

check2 : (-7)^3+7*7^2+4*(-7)+28=28-28=0