how do you graph an equation when one point is at the center and the other point is in the graph?

Question

how do I graph an equation when one point is at the center and the other point is in the graph? the second point is -7,-7? So whats the equation look like?

Answer 1

I assume that by the centre you mean the origin (0,0) and this point is also on the graph. So we have two points (-7,-7) and (0,0). A straight line can be drawn to pass through these points and it has a slope (0-(-7))/(0-(-7))=7/7=1.

This gives us the equation y=1x+a where a is a constant. But the line passes through (0,0) so when x=0, y=0, which means that a=0 and we can remove the 1 so the equation is y=x.