Question 684410

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


{{{2log (3, (x + 4)) - log (3, (9)) = 2}}}


{{{log (3, (x + 4)^2) - log (3, (9)) = 2}}}


{{{log (3, ((x + 4)^2)/9) = 2}}}


{{{((x + 4)^2)/9 = 3^2}}}


{{{((x + 4)^2)/9 = 9}}}


{{{(x + 4)^2 = 81}}} ------ Cross-multiplying


{{{x^2 + 8x + 16 = 81}}}


{{{x^2 + 8x + 16 - 81 = 0}}}


{{{x^2 + 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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