I was wondering if someone can tell me if my answer is correct for this equation.

20x-y=-20. By substituting x and y for 0 I got the following.

y=-20 and x=-1 (0,-20) (-1,0)

Thanks.

Not quite: the sign for the y intercept is wrong. When x =0, y =+20.

Yes, you forgot that -y = -20, so y becomes 20.