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Factor. A) x^2-4x+3 B)x^2+5x-24

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shawnwifey16 | Student, Undergraduate | Honors

Posted April 27, 2013 at 11:58 AM via iOS

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Factor. A) x^2-4x+3 B)x^2+5x-24

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pramodpandey | College Teacher | Valedictorian

Posted April 27, 2013 at 12:13 PM (Answer #1)

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We have given

A.  `x^2-4x+3`

factorise 3 as 3.1

`3=3xx1`

`x^2-(3+1)x+3`

`=x^2-3x-x+3`

`` `=x(x-3)-1(x-3)`

`=(x-3)(x-1)`     ( brackets are equal so factor out )

`B. x^2+5x-24`

`we write 24=8xx3`

`x^2+(8-3)x-24`  ,

in bracket we take minus because last term has minus sign.

`=x^2+8x-3x-24`

`=x(x+8)-3(x+8)`

`=(x+8)(x-3)`   (brackets are same so factor out)

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spompeo4 | eNoter

Posted April 27, 2013 at 2:05 PM (Answer #2)

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A. (x-3)(x-1) b. (x+8)(x-3)
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oldnick | Valedictorian

Posted April 27, 2013 at 11:59 PM (Answer #3)

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`A)`    `x^2-4x+3`      find soluton of  `x^2-4x+3=0`

`Delta= 16-4(3)=4>0`  has two solution

`x=(4+-sqrt(4))/2=(4+-2)/2`     `x_1=3`     `x_2= 1`

The poliniom is decomponed in:

     `(x-x_1)(x-x_2)= (x-1)(x-3)`

``

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oldnick | Valedictorian

Posted April 28, 2013 at 12:12 AM (Answer #4)

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`B)`   `x^2+5x-24=0`

`Delta= 25-4(-24)=121>0`   Two real different solutions.

`x=(-5+-sqrt(121))/2=(-5+-11)/2`

`x_1=3`    `x_2=-8`

`x^2+5x-24=(x-3)(x+8)`

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