My Math Forum  

Go Back   My Math Forum > High School Math Forum > Algebra

Algebra Pre-Algebra and Basic Algebra Math Forum


Reply
 
LinkBack Thread Tools Display Modes
August 16th, 2009, 07:03 PM   #1
Newbie
 
Joined: Aug 2009

Posts: 1
Thanks: 0

An impossible compound equality(11th grade)

Please i need help. its the 1st week of school and im lost. I have to solve compound enequality problems that lack and or or.


5x-(4x=3)+2(6x-is greater than or equal to 10x is greater than 4x+4


then

9x+16 is less than or equal to to 4x+3 is less than or grerater to 22x-(2x+6)
okayzee1 is offline  
 
August 16th, 2009, 08:32 PM   #2
Senior Member
 
Joined: Apr 2007

Posts: 2,140
Thanks: 0

Quote:
Originally Posted by okayzee1
5x-(4x=3)+2(6x-is greater than or equal to 10x is greater than 4x+4
I see an error.

Second part will be stated as 9x + 16 ? 4x + 3, where 4x + 3 < 22x - (2x + 6) = 20x - 6 or 4x + 3 > 22x - (2x + 6) = 20x - 6. For the last two inequalities I have just mentioned, the result will be 9 < 16x or 9 > 16x, therefore x > 9/16 or x < 9/16. For 9x + 16 ? 4x + 3, 5x ? -13, therefore x ? -13/5. This inequality must be hold, so since previously we have determined that x > 9/16 or x < 9/16 can possibly be hold, we can ignore x > 9/16 and worry about x < 9/16. Therefore, logically solving this inequality and x ? -13/5 and the answer for the second part of your post is obviously x ? -13/5.
johnny is offline  
August 17th, 2009, 12:04 AM   #3
Global Moderator
 
Joined: Dec 2006

Posts: 20,464
Thanks: 2038

I assume the first problem should be 5x - (4x + 3) + 2(6x - 8) ? 10x > 4x + 4, i.e., 13x - 19 ? 10x > 4x + 4.
You can rewrite that as two inequalities: 13x - 19 ? 10x and 10x > 4x + 4,
which simplify to 3x ? 19 and 6x > 4, i.e., 3x > 2.
As the first inequality implies the second, the solution is x ? 19/3.
skipjack is offline  
Reply

  My Math Forum > High School Math Forum > Algebra

Tags
compound, equality11th, grade, impossible



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
impossible (prove that 0 = 1) KyVanchhay Algebra 16 June 11th, 2013 10:26 PM
11th root of 2 in Z19 ? rleigh Number Theory 2 April 26th, 2013 09:31 PM
Higher level fractions (11th or 12th grade) shikharras Elementary Math 2 January 23rd, 2013 06:45 PM
Impossible to integrate? TheReanimator Calculus 8 October 29th, 2010 04:00 PM
Is this possible or impossible? ITConsultant1996 Elementary Math 3 June 24th, 2009 11:50 PM





Copyright © 2019 My Math Forum. All rights reserved.