Look at the picture pls help me

Which statement explains how you could use coordinate geometry to prove that quadrilateral abcd is a parallelogram? -5 -4 -3 -2 -1 t 1 2 3 4 prove that all sides are congruent and have slopes that are opposite reciprocals prove that segments ad and ab are congruent and parallel prove that opposite sides are congruent and have equal slopes prove that segments bc and cd are congruent and parallel

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.

How can constraints be used to model a real-world situation?