SOLUTION: Solve log4 (m - 3) + log4 (m + 3) = 2 a. sqrt 11 b. 5 c. 1 d. -5.5

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Solve log4 (m - 3) + log4 (m + 3) = 2 a. sqrt 11 b. 5 c. 1 d. -5.5      Log On


   

Question 328844: Solve log4 (m - 3) + log4 (m + 3) = 2
a. sqrt 11
b. 5
c. 1
d. -5.5
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
log%284+%2C%28%28m-3%29%29%29+%2B+log%284+%2C%28%28m+%2B+3%29%29%29+=+2
log%284+%2C%28%28m+-+3%29%28m+%2B+3%29%29%29+=+2
%28m+-+3%29%28m+%2B+3%29+=+4%5E2
m%5E2-9+=+16
m%5E2=25
m=0+%2B-+5.0
However the log function requires positive arguments so m=-5 is not allowed.
highlight%28m=5%29
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.
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b) is the correct answer.
.
.
.
log%284+%2C%28%285-3%29%29%29+%2B+log%284+%2C%28%285+%2B+3%29%29%29+=+2
log%284+%2C%282%29%29+%2B+log%284+%2C%288%29%29+=+2
1%2F2%2B3%2F2+=+2
2=2
Solution verified.