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put this solution on YOUR website! log(x) + log(x-3) = 2·log(2)
Use this rule of logs
log(A) + log(B) = log(AB)
to rewrite the left side,
and the rule
N·log(A) = log(AN) to rewrite
the right side:
log[x(x-3)] = log(22)
log[x(x-3)] = log(4)
Take "anti-logs" of both sides
x(x-3) = 4
x² - 3x = 4
Get 0 on the right:
x² - 3x - 4 = 0
Factor the left side:
(x - 4)(x + 1) = 0
Set each factor on the left = 0
x - 4 = 0 gives x = 4
X + 1 = 0 gives x = -1
We discard the negative answer because
the original equation contains log(x)
and logs may only be taken of positive
numbers.
Edwin
