Question 4776
1. always for y? in a linear system there is just 1 unknown and typically it is x --> you want to find where the line crosses the x-axis, this is where y=0.


2. you graph the equality --> the line, eg y=2x. Then if we want the region defined by y>2x or y<2x, if you cannot see this, just pick any point you like - not on the line, just a random point...how about (6,0).


If we put these into the equation y=2x, we get 0 and 12 ie 0<12 so, whichever half the pont (6,0) is in, this is y<2x, so y>2x is the other half.


Hope that has explained it well enough?


3. the straight line is the physical representation of the equation. That is why we draw graphs, because they are a visual insight into the line (or curve). As such, any point on the line (or curve) will satisfy the equation.


Hope this is all clear? They are very good questions to ask. I just hope i have answered them well enough - pictures are more helpful with this sort of question.


jon