SOLUTION: \log_{2} x + \log_{2} (x+4) = \log_{2} 7

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Question 435693: \log_{2} x + \log_{2} (x+4) = \log_{2} 7
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

Need to be familiar with the Properties of Logarithms











In this example:







 1 = x(x+4)/7     

  7 = x^2 + 4x

 x^2 + 4x - 7 = 0

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

    x+=+%28-4+%2B-+sqrt%2844+%29%29%2F%282%29+

    x+=+-2+%2B-+sqrt%2811%29+

       x = 1.3166   |Tossing out negative solution