Area of quadrilateral formed by the lines 4y−3x−a=0 , 3y−4x+a=0,4y−3x−3a=0 and 3y−4x+2a=0 is

The area of the parallelogram formed by the lines a1x+b1y+c1=0a2x+b2y+d1=0a1x+b1y+c2=0,a2x+b2y+d2=0 is c1−c2d1−d2a1b2−a2b1 sq. units. ∴ Required area =(2a)(a)(4)(−4)−(3)(−3)=2a27