Alberta Free Tutoring And Homework Help For Math 20-1

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Is 4x2 + 8x + 12    factorable?

If so how can I tell whether it is or not?

5 years ago

Answered By Emanouil B

4x2 + 8x + 12 = 4(x2 + 2x + 3)

That's it.


5 years ago

Answered By Mina M

This is a trinomial. I first suggest you look for gcf between the three terms if it’s there. (4 is the gcf)

4x+ 8x + 12 = 4(x+ 2x + 3)

Next you see you have another trinomial. Here, the quickest way to do this is by inspection.

If I multiply (x+a)(x+b),

we have x2+(ax+bx)+ab

or

x2+(a+b)x +ab.

For our trinomial, x+ 2x + 3

We try to find two numbers that multiply to +3 and add to +2. The only numbers that multiply to 3 are 1 and 3 (prime number), and so there are no two numbers that both add to 2 and multiply to 3. This is therefore not factorable.

The trinomial is therefore factorable only by 4, the greatest common factor between the three terms.


5 years ago

Answered By Bahareh M

Yes, it is. 

First, we could take 4 as a factor;

4 (x2 + 2x + 3)

Then the bracket can be spread to; 

4 (x +1) (x + 2)