Question

Find the roots of $5x^2+13x+8=0$ by using quadratic formula.

Answer 1

$\Rightarrow$ The given quadratic equation is $5x^2+13x+8=0$, comparing it with $a{x}^2+bx+c=0$

$\Rightarrow$ We get, $a=5,b=13,c=8$

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

$=\frac{-13\pm \sqrt{(13{)}^2-4(5\left)\right(8)}}{2\left(5\right)}$

$=\frac{-13\pm \sqrt{169-160}}{10}$

$=\frac{-13\pm \sqrt{9}}{10}$

$=\frac{-13\pm 3}{10}$

$\Rightarrow$ $x=\frac{-13+3}{10}$ and $x=\frac{-13-3}{10}$

$\therefore$ $x=-1$ and $x=\frac{-8}{5}$