Consider graph fx x2 5 A find an equation of the secant lin

Consider graph f(x) = -x^2 +5
A) find an equation of the secant line joining points (-1,4) and (2,1)
B) use the mean value theorem to determine a point c in the interval (-1,2) such that the tangent line at c is parallel to secant line
C) find an equation of the tangent line through c

(Please include step by step calculation for part A, part B, and part C)