SOLUTION: please help me find the value of x log(base1/7)(x)+log(base1/7)(5x-28)=-2 I tried and seem to get a quadratic equation with no solution (negative sqrt).

Question 594666: please help me find the value of x
log(base1/7)(x)+log(base1/7)(5x-28)=-2
I tried and seem to get a quadratic equation with no solution (negative sqrt).

Answer by lwsshak3(11628) (Show Source): You can put this solution on YOUR website!
please help me find the value of x
log(base1/7)(x)+log(base1/7)(5x-28)=-2
log1/7(x)+log1/7(5x-28)=-2
place under single log
log1/7[x(5x-28)]=-2
convert to exponential form
(1/7)^-2=x(5x-28)
(1/7^-2)=5x^2-28x
7^2=5x^2-28x
49=5x^2-28x
5x^2-28x-49=0
(x-7)(5x+7)=0
x=-7/5 (reject, x>0)
or
x=7

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