Write an equivalent expression to x-9y+ 7. Choose the correct answer below.
A. X-9y + 7 = 7(x - 9y + 1)
B. X-9y + 7 = x + 7 + 9y
C. X-9y + 7 = x + 7 + (-9y)
D. X-9y+ 7 = x-(-9y) + 7

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.