`(2x - 6y)^(2) - (6y + 8x)^(2) = "________"`

The number of second degree terms in the expression 2x^(3)-3x^(2)y+5x^(2)-6y^(2)+8x^(2)y-4x^(2)y^(2) is _____

Add: 8x^(2) - 5xy - 3y^(2), 2xy - 6y^(2) + 3x^(2) and y^(2) + xy - 6x^(2)

If the circles x ^(2) + y ^(2) - 8x - 6y + c= 0 and x ^(2) + y ^(2) - 2y + d =0 cut orthogonally, then c + d equals

The equation of the circle which cuts orthogonally the three circles x^(2) + y^(2) + 4x + 2y + 1 = 0 , 2x^(2) + 2y^(2) + 8x + 6y - 3 = 0 , x^(2) + y^(2) + 6x - 2y - 3 = 0 is

For the circles x^(2) + y^(2) - 2x + 3y + k = 0 and x^(2) + y^(2) + 8x - 6y - 7 = 0 to cut each other orthogonally the value of k must be

The number of common tangent to the circles x^(2) + y^(2) + 4x - 6y - 12 = 0 and x^(2) + y^(2) - 8x + 10y + 5 = 0 is

Two circles x^(2) + y^(2) - 4x + 10y + 20 = 0 and x^(2) + y^(2) + 8x - 6y - 24= 0