Question

Solve the equation using formula.

$2x^2+\frac{x-1}{5}=0$

• A. $x=\frac{-1\pm \sqrt{10}}{4}$
• B. $x=\frac{-1\pm \sqrt{41}}{20}$
• C. $x=\frac{1\pm \sqrt{41}}{20}$
• D. $x=\frac{1\pm \sqrt{10}}{4}$

Answer 1

The correct option is B $x=\frac{-1\pm \sqrt{41}}{20}$

Given equation is $2x^2+\frac{x-1}{5}=0$
$\therefore 10x^2+x-1=0$
Applying qudratic formula,
$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$
$a=10,b=1,c=-1$

$\therefore x=\frac{-1\pm \sqrt{1+40}}{20}$

$\therefore x=\frac{-1\pm \sqrt{41}}{20}$

$\therefore$ roots of the given equation are $\frac{-1\pm \sqrt{41}}{20}$