We'll impose the constraints of existence of
logarithms:
3x+8>0
x>-8/3
2x+2>0
x>-1
x-2>0
x>2
The
interval of admissible values for x is (2, +infinite).
Now,
we'll solve the
equation:
ln(3x+8)=ln(2x+2)+ln(x-2)
Since
the logarithms have the matching bases, we'll apply the product rule to the right
side:
ln(3x+8) =
ln[(2x+2)*(x-2)]
Since the bases are matching, we'll apply
one to one rule:
3x + 8 =
[(2x+2)*(x-2)]
We'll remove the brackets from the right
side:
3x + 8 = 2x^2 - 4x + 2x -
4
We'll move all terms to the right side and we'll use
symmetric property:
2x^2 - 4x + 2x - 4 - 3x - 8 =
0
2x^2 - 5x - 12 = 0
We'll
apply quadratic formula;
x1 = [5 + sqrt(25 +
96)]/4
x1 = (5+11)/4
x1 =
16/4
x1 = 4
x2 =
-6/4
x2 =
-3/2
Since the second solution is not in the
interval of admissible values, we'll reject it. The only valid solution is x =
4.
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