A curve has equation y = f(x). (a) Write an expression for the slope of the secant line through the points P(8, f(8)) and Q(x, f(x)). Of (x) - f(8 ) X - 8 Of(8) - 8 f( x ) - X Of ( x) - X f(8) - 8 O X - 8 f ( x) - f(8) (b) Write an expression for the slope of the tangent line at P. O lim f (x ) - f(8 ) X - 0 X - 8 O lim f ( x ) - x x -0 f(8) - 8 lim X - 8 x- 8 f(x) - f(8) O lim f ( x) - f(8) X-8 X - 8