Algebra nation checking your understanding topic 6

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

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

Which of the following contains a variable?