( 41 ) If for the quadratic equation ax2 + bx + c = 0, the difference of the roots is the same
as their product, then the ratio of the roots is
( a )
a b
a b
+
- ( b )
b c
b c
+
- ( c )
c a
c a
+
- ( d ) none of these
( 42 ) The integral values of m for which the roots of the equation
mx2 + ( 2m - 1 ) x + ( m - 2 ) = 0 are rational for rational k are given by
( a ) k ( k + 1 ) ( b )
4
k2 - 1 ( c )
4
k ( k + 2 ) ( d ) none of these
04 - QUADRATIC EQUATIONS Page 7
( Answers at the end of all questions )
( 43 ) If x2 + 6x - 27 > 0 and - x2 + 3x + 4 > 0, the x lies in the interval
( a ) ( 3, 4 ) ( b ) [ 3, 4 ] ( c ) ( - 9, 3 ] ∪ [ 4, 9 ) ( d ) ( - 9, 4 )
( 44 ) The roots of the equation 7 x 1
log 7 ( x2 4x 5 )
-
-
=
+
are
( a ) 2, 3 ( b ) 7 ( c ) - 2, - 3 ( d ) 2, - 3
( 45 ) If 2, 3 are roots of the equation 2x3 + mx2 - 13x + n = 0, then the values of m and
n are
( a ) - 5, - 30 ( b ) - 5, 30 ( c ) 5, 30 ( d ) none of these
( 46 ) If sin α and cos α are the roots of the equation ax2 + bx + c = 0, then
( a ) a2 + b2 - 2ac = 0 ( b ) a2 - b2 + 2ac = 0
( c ) ( a + c )2 = b2 + c2 ( d ) ( a - c )2 = b2 + c2
( 47 ) If the equations ax2 + 2cx + b = 0 and ax2 + 2bx + c = 0 ( b ≠ c ) have a common
root, then a + 4b + 4c =
( a ) 0 ( b ) 1 ( c ) - 1 ( d ) none of these
Answers
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
a d c b c a b a b c a c a b b b c b b a
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
a b b a d a,b a c,d a a c c c b b d b a c b
41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
b a a a b b,c a