8th grade math
posted by roy .
if you know that AB=0 and A not=to B, what can you say about the equation Ax+By=1? Describe the graph.

if in Ax + By = 1, AB = 0
then either A =0 or B=0
If A=0, then you have the horizontal line y = 1/B
if B=0, then you have the vertical line x = 1/A 
The line above goes through points (4,5) and (0,3). What point will the line above go through when y is equal to 8?

You can just look in the back of the textbook, but here is what it says:
The equation will be either
Ax = 1 or By = 1; the graph will be either a vertical or horizontal line. 
Here is what I personally wrote:
Either A or B must equal 0, so the equation Ax+By+1 in standard form would either be Ax=1 or By=1. The graph would either be a vertical line or a horizontal line. 
OOPS. Sorry I accidentally posted the same thing twice. :D