The function is  and point is .

Change of base formula for logarithm property: .

Apply derivative on each side with respect to .

.

Find slope at the point .

Substitute  in .

.

Slope of a tangent line is .

Point-slope form of a line equation is .

Substitute  and  in point-slope form.

.

The tangent line equation is .

Graph :

Graph the function  and tangent line is  :

The tangent line equation is .