Somebody can help me

Which expression is equivalent to 8(k + m) − 15(2k + 5m)?

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.

Show your workcan a right triangle have this sides? *how to prove it without using the pythagorean theorema*