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23 votes
How do you expand double brackets

2 Answers

9 votes

Answer:

Explanation:

Expanding double brackets is easy. Let me give u an example :

(x+5)(x+1)

so the way i do it is

1.Write the second bracket (x+1) twice :

(x+1) (x+1)

2. split the first bracket (x+5) like this :

x(x+1) +5(x+1)

3. Simplify

x*x = x²

x*1 = 1x

5*x = 5x

5*1 = 5

x² + 1x + 5x + 5 = x² + 6x + 5

so the final answer is gonna be x² + 6x + 5

in order to factorize it, u basically do the following :

1. Find two numbers, that multiply to give the last number (a.k.a 5 ) and add to give the middle number (a.k.a 6) The middle number is the sum, and the last number is the product.

so u write all the combo's that make the number 5 :

1 x 5

The two number's are gonna be 1 & 5, because 1 + 5 = 6 (the sum) and 1 x 5 = 5 (the product)

This example is easy since it doesn't include any negative numbers, so u just do = (x+1) (x+5) or (x+5) (x+1) same thing ;-;

I think u should just ask a teacher or watch a tutorial or smthn, this is like the worst explanation ever. But yeah once u know the method, you'll find expanding double brackets rly easy.

User Hooknc
by
3.1k points
6 votes
You pull them and they expand :) !!!! Yea
User Adrian Godong
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3.2k points