8.) /(3-2x) divided by (2+x)/ < 4

/ means absolute value

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- Oct 6th 2006, 07:11 PM^_^Engineer_Adam^_^Help Inequalities with absolute
8.) /(3-2x) divided by (2+x)/ < 4

/ means absolute value - Oct 7th 2006, 12:31 AMearbothgraph solution only
- Oct 7th 2006, 12:31 AMCaptainBlack

|(3-2x)/(2+x)|<4,

means:

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

Now its a good idea to sketch (3-2x)/(2+x), (see attachment)

Now solving (3-2x)/(2+x) = -4, gives x=-11/2 and so

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

when x<-11/2, and alsowhen x>-2 (where the vertical asymtote is).

Now solve (3-2x)/(2+x) = 4, gives x=-5/6 and so:

(3-2x)/(2+x) < 4 for x>-5/6m and also when x<-2.

Combining these we see that both inequalities are satisfied when

x<-11/2 or x>-5/6.

RonL - Oct 7th 2006, 01:21 AMearboth
Hi,

here I am again. You already know the solution of your problem, because CaptBlack has done it. I promised to come back with a solution. So here are my two cents:

abs((3-2x)/(2+x)) < 4 , x ≠ -2

First remove the absolute value:

A) (3-2x)/(2+x) > -4 and B) (3-2x)/(2+x) < 4

A) Multiply by the denominator. There are 2 possibilities:

A1) 3-2x > -4*(2+x) and x > -2

3 - 2x > -8 - 4x

11 > -2x

x < (-11)/2 and x > -2 that means: no solution

A2) 3-2x < -4*(2+x) and x < - 2

3 - 2x < -8 - 4x

11 < -2x

x < (-11)/2 and x < -2 that means: this set belongs to the solution

B) Multiply by the denominator. There are 2 possibilities:

B1) 3-2x < 4*(2+x) and x > -2

3 - 2x < 8 + 4x

-5 < 6x

x > (-5)/6 and x > -2 that means: this set belongs to the solution

B2) 3-2x < 4*(2+x) and x < -2

3 - 2x < 8 + 4x

-5 < 6x

x > (-5)/6 and x < -2 that means: no solution

tschüss

EB