how are you supposed to find the slope? ... straight power rule derivative, or derivative from the limit of a difference quotient?
i think what he is trying to say is...
remember the derivative is going to be the slope...
if the slope is -12 then m=-12 and u have (x,y)-> (1, 394)
so solve for b in y=mx+b
394=-12(1)+b
then u have the equation for the line tangent to the point
correct me if im wrong, i just learned this last week =/