Solve for x.

Question

Solve for x.

 

Log   (x+7) + log   (x-7) = 5 

      2                  2                     

 

The solution(s) is/are x = ?

 

(type an integer or a simplified fraction. Use a comma to separate answers as needed)

Answer 1

log ₂ ( X+7) + log₂ ( X -7 ) = 5 = log₂ 2⁵ = log₂ 32

 

   ( X + 7 ) ( X - 7 ) = 32

 

     X^2 - 49 = 32

 

     X^2 = 81

 

       X = ± 9

 

 

       X = 9  is the only acceptable answer .

 

    Test:

              log ₂ ( 16) + log ₂ 2 = 4 + 1 = 5