Two questions

Is the first one right, I did it with one teacher using a t chart and that's the solution I got.

First, Can you solve for y and get an accurate graph on a graphing calculator(where there are no points plotted that should not be)

I can see some working on the calculator but in this example and one other there are points which are graphed that do not fulfill the initial equation.

for example (2,1)

People tell me not to always use t charts but with examples like this I question not using t charts.