Use the equation x^2-xy+y^2-1. a. find four points on the graph of the equation
b. Show that if (a, b) is on the graph, then (-a,-b) is also on the graph
c. Sketch the graph

The answer would be (B), I think but I hope you get this right

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.