How would I express the coordinates for y20 by x(-20)

If you mean the point where x is -20 and y is 20, that would be expressed as (-20,20)

Thank you so much. Sorry if you thought I was being impatient. I have no clue how I managed to do that. I will be careful to make sure it doesn't happen again. Thanks again.

To express the coordinates for the point with y-coordinate 20 and x-coordinate -20, you would write it in the form (x, y). Therefore, the coordinates for y20 by x(-20) would be (-20, 20).