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
November 28th, 2009, 03:15 PM   #1
Member
 
Joined: Nov 2009

Posts: 49
Thanks: 0

where do i start ?.....

I have the answers but i have no idea where to begin
Attached Images
File Type: jpg mathhhhh.jpg (7.7 KB, 101 views)
peterle1 is offline  
 
November 28th, 2009, 03:24 PM   #2
Member
 
Joined: Nov 2009

Posts: 49
Thanks: 0

Re: where do i start ?.....

This is to be done without calculator
peterle1 is offline  
November 28th, 2009, 04:10 PM   #3
Newbie
 
Joined: Oct 2009

Posts: 6
Thanks: 0

Re: where do i start ?.....

The answers is a=2, b=-1 and c=7?
maykon.caique is offline  
November 28th, 2009, 04:13 PM   #4
Member
 
Joined: Nov 2009

Posts: 49
Thanks: 0

Re: where do i start ?.....

the question is where do i start and how do i do it, but those answers are correct
peterle1 is offline  
November 28th, 2009, 04:20 PM   #5
Newbie
 
Joined: Oct 2009

Posts: 6
Thanks: 0

Re: where do i start ?.....

Solve everything with systems of equations:

2a-3b=7
3a+b=7
maykon.caique is offline  
November 28th, 2009, 04:22 PM   #6
Member
 
Joined: Nov 2009

Posts: 49
Thanks: 0

Re: where do i start ?.....

i dont understand, what happened to the x's and where do those 7 come from
peterle1 is offline  
November 28th, 2009, 04:24 PM   #7
Newbie
 
Joined: Oct 2009

Posts: 6
Thanks: 0

Re: where do i start ?.....

Sorry, I was wrong.

2a-3b=7
3a+b=5
c=7


Look to the two equations.
maykon.caique is offline  
November 28th, 2009, 06:42 PM   #8
Global Moderator
 
Joined: Dec 2006

Posts: 21,127
Thanks: 2336

The question should have been "If (2a - 3b)x + (3a + b)x + c ?7x + 5x + 7, find the values of a, b and c." For that to be an identity, the two polynomials must be essentially the same.
skipjack is offline  
November 28th, 2009, 08:04 PM   #9
Newbie
 
Joined: Oct 2009

Posts: 6
Thanks: 0

Re: where do i start ?.....

Yes... Is this....
maykon.caique is offline  
November 28th, 2009, 09:50 PM   #10
Global Moderator
 
The Chaz's Avatar
 
Joined: Nov 2009
From: Northwest Arkansas

Posts: 2,767
Thanks: 5

Re: where do i start ?.....

Quote:
Originally Posted by peterle1
i dont understand, what happened to the x's and where do those 7 come from
Peter,
Two polynomials are equal only if each term is the same. "term" is actually an important vocabulary word, by the way.
Another way to think of it is to match the "coefficients".

The coefficients on the left are
(2a - 3b)
(3a + b) and
c,
And these should equal 7, 5, and 7 respectively (the coefficients from the right).
That's where you get the equations
2a-3b=7
3a+b=5 and
c =7
The first two equations can be solved using the elimination or substitution method.

p.s. as some post-lobotomy joker might mention, using matrices is possible, but I'm guessing that's beyond the scope of your current studies.
The Chaz is offline  
Reply

  My Math Forum > High School Math Forum > Algebra

Tags
start



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Where do I start? luckymarine Algebra 1 August 17th, 2011 08:11 PM
I don't know where to start! Vurg New Users 9 September 21st, 2010 01:02 AM
help I do not know where to start. chisolm01 Advanced Statistics 2 July 10th, 2008 04:14 PM
Where should I start? rabbit Elementary Math 6 January 15th, 2008 07:38 PM
Where do i start? NotTimBook Calculus 3 July 29th, 2007 05:22 PM





Copyright © 2019 My Math Forum. All rights reserved.