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OG PS # 32

by akane » Sun Sep 18, 2011 7:11 am
Can someone better show the simplification breakdown? V(16)(20)+(8)(32) all of that in a sq root (V). In the book the break it down to V(16)(20)+(16)(16) but then they have V(16)(20+16) = V16 V20+16 how is that? what happened to one of the 16? Thx!
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by gmatclubmember » Sun Sep 18, 2011 7:31 am
akane wrote:Can someone better show the simplification breakdown? V(16)(20)+(8)(32) all of that in a sq root (V). In the book the break it down to V(16)(20)+(16)(16) but then they have V(16)(20+16) = V16 V20+16 how is that? what happened to one of the 16? Thx!
Here it goes:
Sqrt(16*20+16*16)=sqrt[16(20+16)]=sqrt(16) * sqrt(20+16) = 4*sqrt(36) = 4*6 =24.
Hope this helps...

Cheers
Ami/-
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by chetansharma » Sun Sep 18, 2011 7:41 am
akane wrote:Can someone better show the simplification breakdown? V(16)(20)+(8)(32) all of that in a sq root (V). In the book the break it down to V(16)(20)+(16)(16) but then they have V(16)(20+16) = V16 V20+16 how is that? what happened to one of the 16? Thx!
Hi akane,
sqrt(a*b) can be expanded as sqrt(a)* sqrt(b) .
In the explanation posted by you, 16 is multiplied in both the terms [in sqrt(16*20 +16*16) as in sqrt(a*b+a*c)] so 16 was taken out as sqrt(16*(20+16)) as in [sqrt(a*(b+c))]. The next step sqrt(16*(20+16) = sqrt(16)*sqrt(20+16) was expanded as per the formula explained in the first line.

Hope this helps!!

Regards,
Chetan
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by akane » Mon Sep 19, 2011 7:33 am
Thx guys! I don't know why I couldn't see it earlier, I knew it was something simple I was missing and it was driving me crazy! I appreciate all the help!
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