How do you factor c3−2c2−8c?

2 Answers
BRIAN M.
Oct 19, 2015

The factorization of c3−2c2−8c is

c(c+2)(c−4)

Explanation:

To factor c3−2c2−8c
begin by factoring out the variable c as it is a factor of each unit of the tri-nomial.

c(c2−2c−8)

Next, factor the tri-nomial (c2−2c−8)
by finding the factor of 8 that will subtract to get 2.

1 and 8 2 and 4

Since the second sign of the tri-nomial is subtraction the factors must have different signs.

−4(2)=−8
−4+2=−2

Now factor the tri-nomial into two binomials.

c2−2c−8
(c+2)(c−4)

Now complete the factors.

c(c+2)(c−4)

Here is a video on factoring.

Stefan V.
Oct 19, 2015

c⋅(c+2)⋅(c−4)

Explanation:

Your starting expression looks like this

c3−2c2−8c

Notice that you can use c as a common factor for all three terms. This will get you

c⋅(c2−2c−8)

Now focus on the paranthesis. Notice that you can rewrite that expression as

c2−2c−8=c2+2c−4c−8

=c⋅(c+2)⋅(−4)⋅(c+2)

=(c+2)⋅(c−4)

The expression can thus be factored as

c3−2c2−8c=c⋅(c+2)⋅(c−4)

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