Explanation:
remember, a parallelogram is a quadrilateral with 2 pairs of parallel and equal sides, and 2 pairs of correspondingly equal angles. and its diagonals are intersecting each other in their midpoint.
with that in mind
(i)
because ABCD is a parallelogram, AD = BC, and AB = CD.
and angle A = angle C (and angle B = angle D).
therefore, as AE = FC, this also means that ED = BF.
via SAS (side angle side) it is clear that the triangles ABE and CDF are congruent.
therefore, EB = DF.
as ED is part of AD, and BF is part of BC, it is also clear that ED || BF.
together with ED = BF this means that EB || DF.
so, we have with BEDF 2 pairs of parallel and equal sides. and that is a parallelogram.
(j)
BCDE and ABCG are parallelograms.
so, BC = DE = AG, CD = BE, AB = CG.
due to the midpoint intersection rule of the diagonals of parallelograms, we also know
GE = CG = AB, DG = BG.
and as CG || AB, then also GE || AB.
together with AB = GE that means that AE = BG and AE || BG.
so, we have with ABGE again 2 pairs of parallel and equal sides. and that is a parallelogram.