SOLUTION: Please help me solve this equation: {{{ 2log base 3(x+4)-log base 3(9)=2 }}}

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Question 684410: Please help me solve this equation: +2log+base+3%28x%2B4%29-log+base+3%289%29=2+
Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Please help me solve this equation: +2log+base+3%28x%2B4%29-log+base+3%289%29=2+

2log+%283%2C+%28x+%2B+4%29%29+-+log+%283%2C+%289%29%29+=+2

log+%283%2C+%28x+%2B+4%29%5E2%29+-+log+%283%2C+%289%29%29+=+2

log+%283%2C+%28%28x+%2B+4%29%5E2%29%2F9%29+=+2

%28%28x+%2B+4%29%5E2%29%2F9+=+3%5E2

%28%28x+%2B+4%29%5E2%29%2F9+=+9

%28x+%2B+4%29%5E2+=+81 ------ Cross-multiplying

x%5E2+%2B+8x+%2B+16+=+81

x%5E2+%2B+8x+%2B+16+-+81+=+0

x%5E2+%2B+8x+-+65+=+0

(x - 5)(x + 13) = 0

x = 5________OR________x = - 13 (ignore as log of a number CANNOT be negative)

You can do the check!!

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