Answer
$\dfrac{4-3x}{x^2}$
Work Step by Step
RECALL:
$\\x^{-m}=\dfrac{1}{x^m},m \gt 0$
Use the rule above to have:
$\\=4\left(\frac{1}{x^2}\right) - 3\left(\frac{1}{x}\right)
\\=\dfrac{4}{x^2} - \dfrac{3}{x}$
Make the expressions similar using the LCD which is $x^2$ to have:
$\\=\dfrac{4}{x^2} - \dfrac{3(x)}{x(x)}
\\=\dfrac{4}{x^2} - \dfrac{3x}{x^2}
\\=\dfrac{4-3x}{x^2}$
