Final answer:
The equation of the tangent line to the graph of f at the given point is y = x - 6.
Step-by-step explanation:
The equation of the tangent line to the graph of f at the given point can be found using the slope-intercept form of a linear equation, y = mx + b, where m is the slope and b is the y-intercept. In this case, the slope of the tangent line is equal to the slope of the function f at the given point. The slope of f(x) = x is always 1, so the slope of the tangent line is also 1. The y-intercept of the tangent line can be found by substituting the x-coordinate of the given point (9) and the y-coordinate of the given point (3) into the equation.
Using the formula, y = mx + b, we have:
3 = 1 * 9 + b
3 = 9 + b
b = 3 - 9
b = -6
So the equation of the tangent line is y = x - 6.