Prove that the area of the parallelogram formed by the lines 3x−4y+a=0, 3x−4y+3a=0, 4x−3y−a=0 and 4x−3y−2a=0 is 2a27 sq. units.
The area of a parallelogram is
=|c1−d1||c2−d2||a2b1−a1b2|
=|−a+2a||3a−a||3(−3)−4(−4)|
=a×2a7
=27a2
Hence proved.