English Deutsch Français Italiano Español Português 繁體中文 Bahasa Indonesia Tiếng Việt ภาษาไทย
All categories

2006-12-02 03:45:57 · 4 answers · asked by Anonymous in Education & Reference Homework Help

4 answers

(3x + 5) (3x - 5)

You don't have the standard quadratic form here (ax^2 +- bx +- c)
HOWEVER the number (c value) is a minus square.
Whenever this is the case you know you can factorise the expression into two brackets.

It fact that it's a square number lets you put the same number value in each bracket, while the fact it is a minus number lets you make the number positive in one bracket and negative in the other.

This means that when you expand the brackets out those values cancel themselves out. This takes out the middle (b) value and then leaves you with the correct quadratic expression - one, like you have, with just an a and c value. [You would normally have a certain number of x as well: _x in the quadratic expression.]

So whenever you have a quadratic expression in this format, factorise the a value as you would do normally, then for the other two values put the square root of the c value in each bracket, one positive and one negative.

2006-12-02 03:53:01 · answer #1 · answered by vicki_holmesland 3 · 1 0

(3x+5)(3x-5)

2006-12-02 11:54:31 · answer #2 · answered by bella2003 2 · 0 0

(3x-5)(3x+5)

2006-12-02 11:47:44 · answer #3 · answered by UnceasingFaun 2 · 0 0

(3x-5)(3x+5)

2006-12-02 11:47:16 · answer #4 · answered by smileyface(= 1 · 0 0

fedest.com, questions and answers