The point P(7, -4) lies on the curve y = 4 6 - x 4 (a) If Q is the point (x, find the slope of the secant line PQ (correct to six decimal places) for the following values of x. 6 - X (i) 6.9 тра (ii) 6.99 тра = = (iii) 6.999 тра = (iv) 6.9999 тра (V) 7.1 тра (vi) 7.01 = тра = = (vii) 7.001 тра = (viii) 7.0001 тра = (b) Using the results of part (a), guess the value of the slope of the tangent line to the curve at P(7, −4). m = (c) Using the slope from part (b), find an equation of the tangent line to the curve at P(7, -4).