Question

$4x ^{2} + 16x - 9 = 0$

Answer 1

here is your answer.....

Answer 2

$4 {x}^{2} + 16x - 9 \\ 4 {x}^{2} + 18x - 2x - 9 \\ 2x(2x + 9) - 1(x + 9) \\ (2x - 1)(x + 9) = 0$
Hence
$x = - 9 \: \: \: or \: x = \frac{1}{2}$