# solving inequalities

• Dec 29th 2009, 09:56 PM
jay1
solving inequalities
Please solve the inequalities, (the results in set notation)(Headbang)
1) -2 (3+x)< 4x +4 < 8x
2) [2x - 4] < 10
3) 4 < -z - 4 < 11
• Dec 29th 2009, 10:23 PM
Austen Heller
1. 2 < x < 5 or (2, 5)
2. x < 7 or (-inf, 7)
3. -15 < z < -8 or (-15,-8)
• Dec 30th 2009, 12:17 AM
mr fantastic
Quote:

Originally Posted by jay1
Please solve the inequalities, (the results in set notation)(Headbang)
1) -2 (3+x)< 4x +4 < 8x
2) [2x - 4] < 10
3) 4 < -z - 4 < 11

1) Solve seperately: -6 - 2x < 4x + 4 and 4x + 4 < 8x:

-6 - 2x < 4x + 4 => -10 < 6x => 6x > -10 => x > -10/6.

4x + 4 < 8x => 4 < 4x => 4x > 4 => x > 1.

The answer will be the values of x common to both of these solutions.

Now try the others. If you need more help, please show your work and say where yuo get stuck.

Quote:

Originally Posted by Austen Heller
1. 2 < x < 5 or (2, 5)
2. x < 7 or (-inf, 7)
3. -15 < z < -8 or (-15,-8)

The first answer is wrong - I haven't checked the others.