问题详情

The equations below are linear equations of a system where a, b, and c are positive integers.
ay + bx = c
ay - bx = c
Which of the following describes the graph of at least 1 such system of equations in the standard (x,y)coordinate plane？
I. 2 parallel lines
II. 2 intersecting lines
III. A single line
A.I only
B.II only
C.III only
D.I or II only
E.I, II, or III请帮忙给出正确答案和分析，谢谢！