The equation `12x^2-2y^2-6z^2-2xy-8xy+6xz=0` represents

The equation 12x^(2)+7xy-12y^(2)-18x+y+6=0 represents

The equation 6x^(2)-xy-12y^(2)-8x+29y-14=0 represents a pair of lines, then the angle between them is ..............?

The equation 6x^(2)-xy-12y^(2)-8x+29y-14=0 represents a pair of lines, then the angle between them is ..............?

If the equation 2x^2-2xy-y^2-6x+6y+c=0 represents a pair of lines then c=

The equation 16x^(2)+y^(2)+8xy-74x-78y+212=0 represents

The equation 16x^(2)+y^(2)+8xy-74x-78y+212=0 represents

The equation 16x^(2)+y^(2) +8xy-74x-78y+212 =0 represents