The first limit should contain the expression for the definition of tangent-line slope; the second limit should contain the simplified expression; the third is the value for m.
a) lim_(x→a) [f(x) - f(a)] / (x - a)
b) lim_(x→a) f'(x)
c) lim_(x→a) [f(x) - f(a)] / (x - a) = m
d) lim_(x→a) [f'(x)] = m