" 73.The area of the quadrilateral formed by the lines "4x-7y-13=0,8x-y-39=0,4x-7y+39=0" and "8x-y+13=0" is "

The area of the quadrilateral formed by thelines 4x-7y-13=0, 8x-y-39=0, 4x-7y+39=0, 8x-y+13=0 is

A : The area of the parallelogram formed by 4x-7y-13=0, 8x-y-39=0, 4x-7y+39=0, 8x-y+13=0 is 52. R : The area of the parallelogram formed by a_(1)x+b_(1)y+c_(1)=0, a_(1)x+b_(1)y+d_(1)=0, a_(2)x+b_(2)y+c_(2)=0, a_(2)x+b_(2)y+d_(2)=0 is |((c_(1)-d_(1))(c_(2)-d_(2)))/(a_(1)b_(2)-a_(2)b_(1))|

The orthocentre of the triangle formed by the lines x-7y+6=0,2x-5y-6=0 and 7x+y-8=0 is

Equation of a diameter of the circum circle of the triangle formed by the lines 3x+4x-7=0,3x-y+5=0 and 8x-6y+1=0

The orthocentre of the triangle formed by the lines x - 7y + 6 = 0, 2x - 5y - 6 = 0 and 7x + y - 8 = 0 is

Find the orthocentre of the triangle formed by the lines 4x-7y+10=0,x+y=5 and 7x+4y=15 .