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adm45
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Posts: 23
Joined: Mon Feb 13, 2012 9:39 am
 

Operations

by adm45 Wed Jul 03, 2013 12:46 pm

Please explain the underlying concept on how these changes occur:

Taken From: Made it up
x(y+z)+b(y+z)=8 becomes (y+z)(x+b)=8

How doe you get y+z?


Taken from Guide 1 Chp 1 pg. 16
(5 x 7) + (3x7) = (5+3) x 7 = 8 x7

How do you get (5+3)
jlucero
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Joined: Wed May 12, 2010 1:33 am
 

Re: Operations

by jlucero Wed Jul 03, 2013 6:33 pm

adm45 Wrote:Please explain the underlying concept on how these changes occur:

Taken From: Made it up
x(y+z)+b(y+z)=8 becomes (y+z)(x+b)=8

How doe you get y+z?


Let's say y+z = n (a new variable)
Then from your equation:

xn+bn=8 becomes n(x+b)=8

This is a property (distributive) that you need to know.

adm45 Wrote:Taken from Guide 1 Chp 1 pg. 16
(5 x 7) + (3x7) = (5+3) x 7 = 8 x7

How do you get (5+3)


Think of it this way: if you had five sets of 7s and three more sets of 7s, altogether, you'd have (5+3) eight sets of 7s.

Again, this is one of those mathematical things you haven't had to use in a while, so you just need to learn it.
Joe Lucero
Manhattan GMAT Instructor