Question

Solve $3x^{-2}+7x^{-1}+5=0$

Answer 1

$3x^{-2}+7x^{-1}+5=0$

$\Rightarrow \frac{3}{x^2}+\frac{7}{x}+5=0$

$\Rightarrow 3+7x+5x^2=0$

$\Rightarrow 5x^2+7x+3=0$

$\Rightarrow x=\frac{-7\pm \sqrt{49-60}}{10}$

$\Rightarrow x=\frac{-7\pm \sqrt{11}i}{10}$