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A. 0.051
B 0.778
C 0.861
D 1.857

Explanations too, please.
Studying for star testing and stuck.

2007-05-09 18:54:03 · 6 answers · asked by IN0C3NT 2 in Science & Mathematics Mathematics

6 answers

1.857

log 72 = log[(2^3)*(3^2)]

= 3log2 + 2 log3

2007-05-09 19:20:02 · answer #1 · answered by qwert 5 · 0 0

For this type, try to find how to reach 72 by multiplying the given numbers:
Now 72 = 8*9
which is 2*2*2*3*3
so log 72 = log (2*2*2*3*3)

Now use log (a*b) = log a + log b
to write this as
log 2 + log 2 + log 2 + log 3 + log 3, and using the given values of log 2 and log 3 I expect you will find it comes to answer D.

A slicker method is to use the rule
log (a^n) = n* log a, and so
log ((2^3)*(3^2)
= log 2^3 + log 3^2
= 3* log 2 + 2* log 3.

2007-05-09 19:22:32 · answer #2 · answered by Hy 7 · 0 0

For this answer, no actual calculations are required. via fact the log function on a calculator is to base 10, the question might appear as if this: 10^x = seventy two 10 to the skill of something smaller than a million might provide you an answer that is under 10. there is in basic terms one answer above that has an exponent larger than a million. the respond is D. the 1st area of the question is letting you know what the backside of the log function is. (10^0.301=2 , 10^0.477=3) wish this helped.

2016-10-15 06:26:16 · answer #3 · answered by ? 4 · 0 0

None of the first three answers can be correct -- since the number is greater than 10, the log must be greater than 1. That leaves D by elimination. The brute force solution is to factor 72; conveniently, all the factors are 2s and 3s, so you can just add up a suitable number of the given log figures to get the answer.

2007-05-09 19:30:35 · answer #4 · answered by Anonymous · 0 0

log 72
= log (9 x 8)
= log (3² x 2³)
= log 3² + log 2³
= 2 log 3 + 3 log 2
= 1.857
ANSWER D

2007-05-09 19:41:14 · answer #5 · answered by Como 7 · 0 0

D. 1.857

2007-05-09 19:26:52 · answer #6 · answered by trust2400 3 · 1 0

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