# facotr

• Feb 21st 2008, 05:41 AM
Graffitixgirl
facotr
what do you do with these? these are the only ones i dont get...
(p-5)^2
(x-y)^2
(d-2e)^2
(3p-5q)^2
• Feb 21st 2008, 05:46 AM
Charbel
Quote:

Originally Posted by Graffitixgirl
what do you do with these? these are the only ones i dont get...
(p-5)^2
(x-y)^2
(d-2e)^2
(3p-5q)^2

Um ok .. well it's the same as...

(n)^2 = n x n

sooo

(n+1)^2 = (n+1)(n+1)

(p-5)^2 = p^2 -10p + 25
(x-y)^2 = x^2 - 2xy + y^2
(d-2e)^2 = d^2 - 4de + 4e^2
(3p-5q)^2 = 9p^2 - 30pq + 25q^2
• Feb 21st 2008, 05:47 AM
earboth
Quote:

Originally Posted by Graffitixgirl
what do you do with these? these are the only ones i dont get...
(p-5)^2
(x-y)^2
(d-2e)^2
(3p-5q)^2

I assume that you should expand the bracket.

If so there are 2 different ways to do it:

1. Re-write the square as a product and multiply using the distribution rule

$(p-5)^2 = (p-5)(p-5)$

2. All 4 terms belong to one binomial formula:

$(a-b)^2 = a^2 - 2ab + b^2$

Plug in your terms and values into this formula and you'll get the result immediately.