What's 9k power of 2 minus 12k plus 4

12a(2)b(2)-27a(2)

IN THE BRACKETS ARE THE POWERS

Ok, here's your question:



Give the factors of +4 (this is like trial and error)
They are +1, +2, +4 but also -1, -2, -4.

Now, factors of 9, which are +1, +3, +9 (no need to find negative factors here)

Write them in a certain form, like for example this one;

OOOOOO
OOOOOOOOOOOOO
OOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOO

You obtain +13k when you add the products of 9k and +1, and k and +4. You need to obtain -12k.

By trying different numbers, you'll see that the answer is from;

OOOOOO
OOOOOOOOOOOO
OOOOOOOOOOOOOOOOOO
OOOOOOOOOOOOOOOO

And you factors will be

I know this may be a little confusing, there are several methods, and that's the one I was taught. Post back if you don't understand.

Quote:

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Originally Posted by iruleqwerty1234

12a(2)b(2)-27a(2)

IN THE BRACKETS ARE THE POWERS

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Here's your question;



That's more simple than the previous one;

what are the common factors in and ?

You'll find them be , so factorise by that term and put what remains into brackets;



You'll find your original question if you expand. Now, it happens that the terms in brackets are perfect squares, 4, and 9. From your formula of , further factorise to give;