I have done i. With ii I cannot get an equation that does not include x as a part of the coefficient of x. The answer in the book is px=1-q(y/x). Compared to y=mx+c what are the equivalents of m and c?
$\displaystyle px^2 + qy = x$
Divide by x;
$\displaystyle px + \frac{qy}{x} = 1$
Move the qy/x around;
$\displaystyle px = 1 - \frac{qy}{x}$
Here, you can take the Y as being x and X as being y/x.
This gives:
$\displaystyle pY = 1 - qX$
You can put it in the form Y = mX + c now?