Plot the three points with first coordinate equal to (-2,8) and join them

Answer 1

what do you mean by "first coordinate equal to (-2,8)"?
That's a point, not a coordinate.

If you mean 1st coordinate of -2, then just pick three other numbers for the 2nd coordinate.

If you don't know how to plot points, you need to
(a) read your course material
(b) google the topic

Answer 2

Thanks very much for the response.