Question

find the value of k for each of the following quadratic equation, so that they have two equal roots
2x2+8x-k3 =0​

Answer 1

Answer refer to attachment

Answer 2

For equal roots D=0

$[2(k−12)]^2−4 \times (k−12) \times 2=0$

$4(k−12)^2−4(k−12)×2=0$

$k^2−24k+144−2k+24=0$

or

$k^2 −26k+168=0$

$k^2−14k−12k+168=0$

k(k−14)−12(k−14)=0

(k−12)(k−14)=0

∴k=12or14

∴k=14