If the combined equation of angle bisectors of the lines $x^2 - 2pxy - y^2 = 0$ is $x^2 - 2qxy - y^2 = 0$, then which of the following is true?

The coordinates of the orthocenter of the triangle whose sides are represented by the lines $4x - 7y + 10 = 0$, $x + y = 5$ and $7x + 4y = 15$ are $\ldots$

The combined equation of lines parallel to the coordinate axes and passing through the point of intersection of lines represented by $x^2 - 6xy + 5y^2 + 10x - 14y + 9 = 0$ is $\ldots$

The line $L_1$ given by $\dfrac{x}{p} + \dfrac{y}{2} = 1$ passes through the point $(5,0)$. The line $L_2$ given by $\dfrac{x}{10} + \dfrac{y}{q} = 1$ is parallel to $L_1$. Then the distance between the lines $L_1$ and $L_2$ is...