using first principle, find the slope of a tangent line to the curve f(x) = x^2-3x+5 at x=3

Answer 1

find the limit of
(f(x+h)-f(x))/h
= [((x+h)^2 - 3(x+h) + 5) - (x^2-3x+5)]/h
You should wind up with 2x-3