Find the indefinite integral: $\int (7x^2-2x^6)dx$

Evaluate the indefinite integral: $\int (4x-7{)}^{2}dx$

Evaluate the indefinite integral: $\int (5x^{\frac{2}{5}}+7x^{-\frac{3}{5}}+2)dx$

Evaluate the indefinite integral: $\int \frac{5+4\cos x}{{\sin }^{2}x}dx$

Determine the indefinite integral by performing a trigonometric substitution: 

$\int \frac{x^2}{(16+x^2{)}^2}dx$