Question

Factorise: $x^2-4x-2500$

Answer 1

$x^2-4x-2500=0$ is a quadratic equation where a=1, b=-4 and c=-2500

$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$x=\frac{-(-4)\pm \sqrt{(-4{)}^2-4\times 1\times (-2500)}}{2\times 1}$

$x=\frac{4\pm \sqrt{16+10000}}{2}$

$x=\frac{4\pm \sqrt{10016}}{2}$

$x=\frac{4\pm 4\sqrt{626}}{2}$

$x=\frac{2(2\pm 2\sqrt{626})}{2}$

$x=2\pm 2\sqrt{616}$