Consider the curve

$$y = x^{2}-3x+5.$$
(a) Find the slope of the secant line to the curve through the points $P = (4, 9)$ and $Q = (4+h, \left(4+h\right)^{2}-3\!\left(4+h\right)+5)$.
The slope of the secant line is .

(b) Use your answer from part (a) to find the slope of the curve at the point $P$.
The slope of the curve at $P$ is .

(c) Write an equation of the tangent line to the curve at $P$.
The equation of the tangent line at $P$ is $y =$ .