Question

Find the roots of the quadratic equations $2x^2+x-4=0$.

Answer 1

$2x^2+x-4=0$

$\Rightarrow 2x^2-4x+2x-4=0$

$\Rightarrow 2x(x-2)+2(x-2)=0$

$\Rightarrow (x-2)(2x+2)=0$

$\Rightarrow (x-2)2(x+1)=0$

$\Rightarrow (x+1)(x-2)=0$

$\therefore x=-1,2$

$\therefore$ Roots of the equation are $\{-1,2\}$