Chapter 5:Indices and Logarithms @ganeshie8
\[\frac{ 49^{2n+1}\times14^{6-2n} }{ 56^{2n-5} }\]
Simplify the following
@hartnn
start by factoring 14 and 56
\[==\frac{ 49^{2n+1}\times(7\times2)^{6-2n} }{ (7\times8)^{2n-5} }\]
Do it with 49 as well. You may want to factor all bases down to primes...
okay
\[=\frac{ (7\times7)^{2n+1}\times(7\times2)^{6-2n} }{ (7\times8)^{2n-5} }\]
\[=\frac{ (7\times7)^{2n+1}\times(7\times2)^{6-2n} }{ (7\times2\times2\times2)^{2n-5} }\]
\[=\frac{ 7^{2n+1}\times7^{2n+1}\times7^{6-2n}\times2^{6-2n} }{ 7^{2n-5}\times2^{2n-5}\times2^{2n-5}\times2^{2n-5} }\]
\[=\frac{ 7^{2n+1+2n+1+6-2n}\times2^{6-2n} }{ 7^{2n-5}\times2^{8n-15} }\]
\[=\frac{ 7^{2n+8}\times2^{6-2n} }{ 7^{2n-5}\times2^{8n-15} }\]
\[=7^{2n+8}\times2^{6-2n}\div7^{2n-5}\times2^{8n-15}\]
\[=7^{2n+8-2n+5}\times2^{6-2n-8n+15}\]
\[=7^{13}\times2^{21-10n}\]
@campbell_st
I got \[=7^{13}\times2^{21-10n}\] but the answer in the book say it's \[=7^{13}\times2^{21-8n}\]
Am i correct?
book is right
\[\large{ \frac{ 49^{2n+1}\times14^{6-2n} }{ 56^{2n-5} }\\\\ =\frac{7^{2(2n+1)}\times7^{6-2n}\times2^{6-2n}}{7^{2n-5}\times8^{2n-5}}\\\\ =\frac{7^{4n+2+6-2n}\times2^{6-2n}}{7^{2n-5}\times2^{3(2n-5)}}\\\\ =\frac{7^{2n+8}\times2^{6-2n}}{7^{2n-5}\times2^{6n-15)}}\\\\ =7^{2n+8-2n+5}\times2^{6-2n-6n+15}\\ =7^{13}\times 2^{21-8n} }\]
an \(\color{red}{\text e}\)rror in your working \[=\frac{ 7^{2n+1}\times7^{2n+1}\times7^{6-2n}\times2^{6-2n} }{ 7^{2n-5}\times2^{2n-5}\times2^{2n-5}\times2^{2n-5} }\]\[=\frac{ 7^{2n+1+2n+1+6-2n}\times2^{6-2n} }{ 7^{2n-5}\times2^{\color{red}6n-15} }\]
okay know i get :) yay
Thnx @UnkleRhaukus
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