y = 

Use the change of base formula:

Y = 

Write as a division:

y = 1÷

Invert and multiply:

y = 1·

y = 

Bring the denominator to the numerator with a -1 power 

y = ln(10)·[ln(x)]-1

                       Now we need two formulas 

                       1)  = 

                       and

                       2)  = ·

y = ln(10)·[ln(x)]-1

 = -1·ln(10)·[ln(x)]-2
 = -ln(10)·
 = -

Edwin