For the two circles x2 + y2 = 16 and x2 + y2 - 2y = 0 there is/are
one pair of common tangents
only one common tangent
three common tangents
no common tangent
If C is a point on the line segment joining A(- 3, 4) and B(2, 1) such that AC = 2BC, then the coordinate of C is
(2, 7)
(7, 2)
If a, b, c are real, then both the roots of the equation (x - b)(x - c) + (x - c)(x - a) + (x - a)(x - b) = 0
positive
negative
real
imaginary
C.
real
Given equation can be rewritten as,
3x2 - 2x(a + b + c) + ab + bc + ca = 0
Now, Discriminant,
D = 4(a + b + c)2 - 4 . 3(ab + bc + ca)
= 4(a2 + b2 + c2 - ab - bc - ca)
= 2[(a - b)2 + (b - c)2 + (c - a)2]
0
Hence, roots are real.
The point (- 4, 5) is the vertex of a square and one of its diagonals is 7x - y + 8 = 0. The equation of the other diagonal is
7x - y + 23 = 0
7y + x = 30
7y + x = 31
x - 7y = 30