Can you help me please

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

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.

Matt had 5 library books. he checked out 1 additional book every week without retuening any books. whats the matching equation