4. quadrilateral abcd has diagonals ac and bd. which information is not sufficient to prove abcd is a parallelogram. * 2 points ac and bd bisect each other ab ≅cd and bc ≅ ad ab ≅ cd and ab ll cd ab ≅ cd and bc ll ad

answer: the first graph

step-by-step explanation:

check above link.

graphically?   well, you graph them both, the solutions is where they both intersect each other, since there are two solutions, meaning they will meet twice, or namely the linear will run into the quadratic curve twice, and where they meet, those x,y coordinates are the solutions to the system.