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Factor 2x^3 + 3x^2 + 4x + 6

Step by step, with the reason for every step · Factor by grouping · Algebra 1

Step by step

The question

Question: factor 2x³ + 3x² + 4x + 6.

There are four terms.

So we factor them in pairs.

This is called grouping.

2x3 + 3x2 + 4x + 6

1 Group in pairs

We put the first two together, and the last two together.

= (2x3 + 3x2) + (4x + 6)

From the first pair we take out x².

From the second pair we take out 2.

Both leave the same bracket, 2x + 3.

(2x3 + 3x2) = x2(2x + 3)
(4x + 6) = 2(2x + 3)

Now both parts have 2x + 3 in them.

= x2(2x + 3) + 2(2x + 3)

Careful!

This is not the answer yet.

It is still two parts added.

Factored means one thing times another.

Careful: not done yet: still a + between two parts

2 Same bracket out

2x + 3 is in both parts, so we take it out once.

What is left, x² + 2, goes in the other bracket.

ab + cb = b(a + c)

So we get (2x + 3)(x² + 2).

= (2x + 3)(x2 + 2)

3 Check

Let's check: we multiply it back out.

Each part of the first bracket times each part of the second.

Check: (2x + 3)(x2 + 2) = 2x3 + 4x + 3x2 + 6
= 2x3 + 3x2 + 4x + 6

We get 2x³ + 3x² + 4x + 6 again.

So the answer is right!

Let's look back.

First: group in pairs.

Then: same bracket out.

Last: check.

Answer
= (2x + 3)(x2 + 2)

Your turn

Try this one yourself, then check:

Factor 2x3 + x2 + 10x + 5
Show the answer
(2x + 1)(x2 + 5)

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