Question 142240
Condense the following: 
1. log3 2x+3log3 4x 

= log3 [ 2x*(4x)^3] 

= log3 [ 2x*64x^3]

= log3 [128x^4]
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2. ln72x-2 ln 2 y 

= ln(72x) - ln(2y)2

= ln(72x) - ln(4y^2)

= ln[72x/4y^2]

= ln[18x/y^2]
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Use the Change of base formula
 
Log4 31 
= log(31)/log(4)
= 2.477
======================= 
log7 100 
= log(100)/log(7)
= 2/0.8451
= 2.3666
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Cheers,
Stan H.