Integrate the following w.r.t. x.
1. `x^3`
2. `x-1/x`

Explanation

Let's solve the given integrals step by step.

### Step 1: Integrate \( x^3 \)

To integrate \( x^3 \) with respect to \( x \), we use the power rule for integration. The power rule states that:

\[
\int x^n \, dx = \frac{x^{n+1}}{n+1} + C
...