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Mathematics 6 Online
OpenStudy (anonymous):

How would you simplify this log expression?

OpenStudy (anonymous):

\[2\log_{2} 15-\log_{2} 5+\log_{2} 3\]

ganeshie8 (ganeshie8):

use this :- \(\large k \log_b a = \log_b a^k \)

ganeshie8 (ganeshie8):

\(\large 2\log_{2} 15-\log_{2} 5+\log_{2} 3 \) \(\large \log_{2} 15^2-\log_{2} 5+\log_{2} 3 \) \(\large \log_{2} 225 -\log_{2} 5+\log_{2} 3 \)

ganeshie8 (ganeshie8):

we can simplify further, any ideas how ? :)

OpenStudy (anonymous):

225-5+3=223 ---> new exponent?

ganeshie8 (ganeshie8):

hey no... these are logs, we must use log rules ok :)

ganeshie8 (ganeshie8):

we use below rule next :- \(\large \log_a b - \log_a c = \log_z (\frac{b}{c})\)

OpenStudy (anonymous):

what does z=

ganeshie8 (ganeshie8):

sorry its a typo, it should be a

ganeshie8 (ganeshie8):

thnks for catching :)

ganeshie8 (ganeshie8):

apply that rule, \(\large \log_{2} 225 -\log_{2} 5+\log_{2} 3\) \(\large \log_{2} (\frac{225}{5})+\log_{2} 3\)

OpenStudy (anonymous):

\[\log_{2} 225-\log_{2} 5= \log_{2} (225/5)\]

ganeshie8 (ganeshie8):

yes ! u can simplify the division inside

OpenStudy (anonymous):

45

ganeshie8 (ganeshie8):

\(\large \log_{2} (\frac{225}{5})+\log_{2} 3 \) \(\large \log_{2} 45 +\log_{2} 3 \)

ganeshie8 (ganeshie8):

next we use this rule :- \(\large \log_a b + \log_a c = \log_a bc \)

OpenStudy (anonymous):

\[\log_{2} 135\]

ganeshie8 (ganeshie8):

\(\large \log_{2} 45 +\log_{2} 3 \) \(\large \log_{2} 45 \times 3 \) \(\large \log_{2} 135 \)

ganeshie8 (ganeshie8):

Yes, thats that final simplified form.

OpenStudy (anonymous):

YEAAHHH, thank you!!

ganeshie8 (ganeshie8):

there are oly few log rules we need to remember, to do these...

ganeshie8 (ganeshie8):

np :) you're wlcme !

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