slope of tangent x Question 9 Jezx - 1 Let f(x) = - 42+ 4 VITA , where k is a constant. It is given that f'(-1) = - (a) Find the value of k. (b) Find the equation of the tangent to the graph of y = f(x) at x = 2. x 2 +4 a ) +( X ) = f ' ( x ) = = ( x +h ) =(x2+4 ) - ( xth) = (2 x th ( ath ) = = [ z ( 7 2 14 ) - Math xtk 1 1 ( x th ) = ( z x1 2 + 2