Question

factorise x square+2x -7 =0

Answer 1

$x { } ^ {2} + 2x - 7 = 0$
$ax {}^{2} + bx + c = 0 \: se \: tulna \: karne \: par$
$a = 1 . \: b = 2. \: \: c = - 7$
$x = - b \frac{1}{2a} + \sqrt{b {}^{2} - 4ac } \times \frac{1}{2a}$
$x = - b \times \frac{1}{2a} - \sqrt{b {}^{2} - 4ac} \times \frac{1}{2a}$

therefore
$x = - 2 \frac{1}{2 \times 1} + \sqrt{2 {}^{2} - 4 \times 1 \times - 7 } \times \frac{1}{2 \times 1}$
$x = - 1 + \sqrt{4 + 28} \times \frac{1}{2}$
$x = - 1 + \sqrt{32} \times \frac{ 1}{2}$
$\sqrt{32} = 4 \sqrt{2}$
therefore
$x = - 1 + 4 \sqrt{2} \times \frac{1}{2}$
$x = - 1 + 2 \sqrt{2}$
thus
$x = - 1 - 2 \sqrt{2}$