The area of the figure formed by the lines `ax + by +c = 0, ax - by + c = 0, ax+ by-c = 0` and `ax- by - c = 0` is

If the quadrilateral formed by the lines ax + by + c = 0, a'x + b'y + c' = 0, ax + by + c' = 0,a'x + b'y + c = 0 have perpendicular diagonals, then :

The area of the triangle formed by the line ax+by+c=0 with the coordinate axes is

Area of the rhombus bounded by the four lines, ax +- by +-c = 0 is

Area of the rhombus bounded by the four lines, ax +- by +-c = 0 is

Area of the rhombus bounded by the four lines, ax +- by +-c = 0 is

Slope of the line ax+by+c=0 is

The slope of the line ax + by + c = 0 is "_______" .