Find the integral $\int\frac{1}{x^4}dx$

Find the integral

$\int\frac{dx}{\sqrt{25-9x^2}}$

Find the integral

$\int\frac{\sqrt{x^2+4}}{x^4}dx$

Find the integral

$\int\frac{x}{\sqrt{49+x^2}}dx$

Find the integral

$\int\frac{3}{5x^2}dx$

Find the integral

$\int\frac{1}{\sqrt[4]{x}}dx$

Find the integral

$\int\frac{dx}{x^2}$

Find the integral

$\int\frac{dx}{x^4}$