Solve the logarithmic equation for x. log5(x + 3) − log5(x − 3) = 2?

2016-01-26 5:10 pm

回答 (2)

2016-01-26 5:19 pm

log5(x + 3) − log5(x − 3) = 2
(x+3)/(x-3)=5^2=25
x+3=25x-75
24x=78
x=78/24=13/4=3 1/4
3 1/4 + 3 > 0 yes
3 1/4 - 3 > 0 yes
x=13/4

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2016-01-26 5:16 pm

log5(x + 3) − log5(x − 3) = 2
log5(x + 3)/(x − 3) = 2
(x+3)/(x-3) = 5^2
x+3 = 25(x-3)
x+3 = 25x - 75
25x-x = 3 +75
24x = 78
x = 78/24 = 39/12 = 13/4

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