6. Simplify each expression (prerequisite skill)
A. 3x - 5- X
B. 4x - 5y + x + 7y
C. 6-7y - 1 - 10y
D. 4(3x - y) -2(5x + 6y)
E. 5x - (3x - 9y) + y
F. 2(4x - 6)-769-8) + 3(x - 2y)
G. (9x - 6y) - (9x - 6y)

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.