Question

2x²+4x-16 solve by completing the sqaure method​

Answer 1

Answer:

x = -4 or 2................

Answer 2

Step-by-step explanation:

In order to solve the given quadratic expression it should be equal to zero.

$\therefore \: 2 {x}^{2} + 4x - 16 = 0 \\ dividing \: throughout \: by \: 2 \: we \: find : \\ {x}^{2} + 2x - 8= 0 \\{x}^{2} + 2x = 8....(1)\\now \\ third \: term = ( \frac{1}{2} \times coefficient \: of \: x)^{2} \\ = ( \frac{1}{2} \times 2)^{2} = 1 \\ adding \: 1 \: on \: both \: sides \: of \: equation \: (1) \\ {x}^{2} + 2x + 1 = 8 + 1 \\ \implies(x + 1) ^{2} = 9 \\ \implies \: x + 1 = \pm \: \sqrt{9} \\ \implies \: x + 1 = \pm \: 3 \\ \implies \: x = \pm \: 3 - 1 \\ \therefore \: x = 3 - 1 \: or \: x = - 3 - 1 \\\therefore x = 2 \: or \: x = - 4 \:$