Question

if the root of quadratic 2 X square + kx + 2 equal to zero are equal then find the value of k

Answer 1

eq-

${x}^{2} + kx + 2 = 0$

since roots are equal:-

${b}^{2} - 4ac = 0 \\ \\ {k}^{2} - 4 \times 2 \times 2 = 0 \\ {k}^{2} - 16 = 0 \\ {k}^{2} = 16\\ k = \sqrt{16} \\ k = 4$

Answer 2

Hey Cybertronian!!

＼(^_^)／

${eq}^{n} = 2 {x}^{2} + kx + 2 = 0 \\ \\ and \: for \: equal \: roots \\ \: we \: have: \\ d = 0 \\ = > {b}^{2} - 4ac = 0 \\ = > {k}^{2} \times 4(2)(2) = 0 \\ = > {k}^{2} = 16 \\ = > k = ±4 \\ \therefore\fbox{ \: \:either \: \: k = + 4 \: \: or \: \: k = - 4}$