How do you make a number in between 8 and 9

Anyone know? is appreciated! will mark brainliest if correct!

In the figure below, ∠dec ≅ ∠dce, ∠b ≅ ∠f, and segment df is congruent to segment bd. point c is the point of intersection between segment ag and segment bd, while point e is the point of intersection between segment ag and segment df. the figure shows a polygon comprised of three triangles, abc, dec, and gfe. prove δabc ≅ δgfe.

Which shows one way to determine the facts of x3+4x2+5x+20 by grouping