Question

Find the roots of the following quadratic equation by using the quadratic formula
$4x^2+3x+5=0$

• A. $\frac{3+\sqrt{71i}}{8}$
• B. $\frac{3+\sqrt{89i}}{8}$
• C. $\frac{-3\pm \sqrt{71i}}{8}$
• D. $\frac{-3\pm \sqrt{89i}}{8}$

Answer 1

The correct option is C $\frac{-3\pm \sqrt{71i}}{8}$

Roots of the quadratic equation $a{x}^2+bx+c=0$ are : $\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

Roots of above equation are :$\frac{-3\pm \sqrt{3^2-\mathrm{4.4.5}}}{2.4}$

$\Rightarrow \frac{-3\pm \sqrt{71}i}{8}$