Question

Evaluate :
$x(2x+5)=25$

Answer 1

$x(2x+5)=25$

$\Rightarrow 2x^2+5x-25=0$

$\Rightarrow 2x^2+10x-5x-25=0$

$\Rightarrow 2x(x+5)-5(x+5)=0$

$\Rightarrow (2x-5)(x+5)=0$

So $x=\frac{5}{2}$ or $x=-5$.