The number of integral values of $m$ for which the equation, $1 + m ^ { 2 } x ^ { 2 } - 21 + 3 m x + 1 + 8 m = 0$ has no real root, is (1) 2 (2) 3 (3) Infinitely many (4) 1
The number of integral values of $m$ for which the equation, $1 + m ^ { 2 } x ^ { 2 } - 21 + 3 m x + 1 + 8 m = 0$ has no real root, is\\
(1) 2\\
(2) 3\\
(3) Infinitely many\\
(4) 1