+0  
 
0
1288
2
avatar

log5 180 − log5 75 − log5 60

 Feb 21, 2016

Best Answer 

 #2
avatar+33659 
+20

1.  Use the fact that logbx - logby = logb(x/y)

log5180 -  log575 - log560 = log5(1/25) → log5(25-1) → log5(5-2)

 

2.  Now use the fact that logb(bm) = m

log5(5-2) = -2

 

So log5180 -  log575 - log560 = -2

.

 Feb 21, 2016
 #1
avatar+333 
0

The exact value is -2. 

 Feb 21, 2016
 #2
avatar+33659 
+20
Best Answer

1.  Use the fact that logbx - logby = logb(x/y)

log5180 -  log575 - log560 = log5(1/25) → log5(25-1) → log5(5-2)

 

2.  Now use the fact that logb(bm) = m

log5(5-2) = -2

 

So log5180 -  log575 - log560 = -2

.

Alan Feb 21, 2016

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