Y-f(x) -5
3. The graph of a twice-differentiable function y=f(x) is shown in the figure above. Which of
the following is true?
(A) f(-1) (B) f(-1) (C) f'(-1) (D) f"(-1) (E) f"(-1)

thx and have a good day

if triangle abc is congruent to triangle def, their interior angles are congruent, because congruent parts of congruent triangles are congruent (cpctc).

that means ∠d is congruent to ∠a; ∠d is equal to 8x - 2.

interior angles of all triangles add to equal 180 degrees, so you can set the sum of these interior angle values equal to 180 and solve for x.

180 = (8x - 2) + 22 + 72

180 = 8x - 2 + 22 + 72

180 = 8x + 92

88 = 8x

11 = x

x = 11