I haven't much time yet so I'll help you with the first 2 questions:

1. If you have the equation of a line in the form

then yields the distance of the origin to this line.

Since your lines are parallel you only have to calculate the difference of the 2 distances of the origin.

Therefore and which will give

2. The equation describes a line with the x-intercept a and the y-intercept b.

Thus the sum of the intercepts is 24.