Can someone please help me with this it’s due tonight

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Given: ae ≅ ce ; de ≅ be prove: abcd is a parallelogram. we have that ab || dc. by a similar argument used to prove that △aeb ≅ △ced, we can show that △ ≅ △ceb by. so, ∠cad ≅ ∠ by cpctc. therefore, ad || bc by the converse of the theorem. since both pair of opposite sides are parallel, quadrilateral abcd is a parallelogram.

Solve the equation. 2x - 8(x+1)= 6(2x - 3)