A) We can first start with the how: our equation is 2x+y=3. First, subtract 2x from each side. We get y=-2x+3. Our Y variable is isolated.
B) Now we can describe which points our equation goes through. One of them is obvious in our form, and that is (0,3) or our y-intercept. Another 2 would be branching off that line, such as (1,1) or (-1,5)
C) To make our system inconsistent, we can easily make another equation, with same slope, but the y-intercept has to be different. Our equation can be y=-2x+2, y=-2x+4, or even y=-2x+3.00000001.
Hope this helps you.