Algebra 1 Question. I don't quite understand simplifying.?

2009-07-13 4:44 pm
Simplify: 3x^2 + 2x - 8 / 12 - 5 - 3x^2

回答 (3)

2009-07-13 5:03 pm
✔ 最佳答案
(3x^2 + 2x - 8)/(12 - 5 - 3x^2)
= (3x^2 + 6x - 4x - 8)/(7 - 3x^2)
= [(3x^2 + 6x) - (4x + 8)]/(7 - 3x^2)
= [3x(x + 2) - 4(x + 2)]/(7 - 3x^2)
= [(x + 2)(3x - 4)]/(7 - 3x^2)
2009-07-13 7:52 pm
Error in question I think.

Should be 12 - 5 x - 3x^2 on denominator.

( 3 x - 4 ) ( x + 2 )
--------------------------
( 4 - 3 x ) ( 3 + x )

- ( x + 2 )
------------------
( 3 + x )
2009-07-13 5:04 pm
(3x^2 + 2x - 8) / (12 - 5 - 3x^2) [factor first]
= (3x - 4)(x + 2) / (3 + x)(4 - 3x)
= (3x - 4)(x + 2) / (3 + x)(-1)(3x - 4) [now the (3x-4) can be cancelled]
= (x + 2) / (3 + x)(-1)
= (-x - 2) / (3 + x)


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