Which is the only solution to the equation log3(x2 + 6x) = log3(2x + 12)?
x = -6, x = -2, x = 0, x = 2, x = 6
Solution:
It is given that expression is
log3(x2 + 6x) = log3(2x + 12)
Let us make use of the logarithmic rule
logb x = logb y
So x = y
x2 + 6x = 2x + 12
By subtracting 2x on both sides
x2 + 6x - 2x = 2x + 12 - 2x
x2 + 4x = 12
It can be written as
x2 + 4x - 12 = 0
x2 + 6x - 2x - 12 = 0
Taking out the common terms
x(x + 6) - 2(x + 6) = 0
(x + 6)(x - 2) = 0
So we get
x + 6 = 0 and x - 2 = 0
x = - 6 and x = 2
As x = -6 does not satisfy the equation, x = 2 is the only solution.
Therefore, the only solution is x = 2.
Which is the only solution to the equation log3(x2 + 6x) = log3(2x + 12)?
Summary:
The only solution to the equation log3(x2 + 6x) = log3(2x + 12) is x = 2.
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