May someone help me with questions 8-11 because I'm very confused on my calculus review

ax, x51 f ( x ) = 8.) Let bx2 +x+1, x>1 Find all possible values of @ and b such that f ( x) is differentiable at * =1. Show proper justification.-F(x ) (-1) (5) - (:2) (3 ) (5 ) -5 +6 25 ( or - (57 ) 25 9.) If f(x)=2x-+4 , which of the following will calculate the derivative of f(x) ? [2(x+4x)2+4]-(2x2+4) (A) 4x lim (2x2+4+4x)-(2x2+4) (B) 4x +0 4x lim [2(x+ 4x)2+4]-(2x2+4) (C) 4x +0 4x (2x2+4+4x)-(2x2+4) (D) 4x 10.) Let h(x) = f(x)xg(x) Find h (2) 6 Ay (A) -2 (-1,5) (B) 1 (C) 7 (D) -1 (3,1) (6, 3) -1 1 11.) What is 9 (3) ? =(x) (3,-1) Stop after! (7,-4 ) (1,-5)