Question

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

• A. $1,-\frac{8}{5}$
• B. $-1,-\frac{8}{5}$
• C. $-1,\frac{8}{5}$
• D. $1,\frac{8}{5}$

Answer 1

The correct option is B $-1,-\frac{8}{5}$

Given:

$5x^2+13x+8=0$

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

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

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

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

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

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