Question

Solve $x^2-10x+6=0$, using formula. Give your answer correct to 2 decimal places.

Answer 1

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

where $a=1,b=-10,c=6$

Substituting the above values we get

$x=\frac{10\pm \sqrt{100-4\times 1\times 6}}{2\times 1}$

$=\frac{10\pm \sqrt{100-24}}{2}$

$=\frac{10\pm \sqrt{76}}{2}$

$=\frac{10\pm \sqrt{4\times 19}}{2}$

$=\frac{10\pm 2\sqrt{19}}{2}$

$=5\pm \sqrt{19}$

$=5\pm 4.3588$

$=5+4.3589,5-4.3589$

$\therefore x=9.3589,0.6411$