¿Es posible encontrar un numero a para que 4 x (-a) se positivo?

What is the least common multiple of 16 and 3?

Ijust need these 2 questions answered (the second pic is just confirmation i'm not confident in that answer)

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.