Question

19. For what values of k the equation x2 + 4kx + 4
= 0 has equal roots?
(a) +2 (b) 1 (c) 4vcznnjhu​

Answer 1

Explanation:

When the equation has equal roots, D=0

$d \: = 0 \\ b {}^{2} - 4ac = 0 \\ (4k) {}^{2} - 4(1)(4) = 0 \\ 16k {}^{2} - 16 = 0 \\ 16k { }^{2} = 16 \\ k {}^{2} = \frac{16}{16} \\ k {}^{2} = 1 \\ k = 1 \\ or \\ k = - 1$