It looks like the equation you provided is not fully clear. Could you confirm or clarify it for me?

From the given part, it seems like you want to integrate something like:

$\int \left( \frac{l(x)}{5} - x^3 + x \right) \, dx$

But the part l(x) seems like a potential typo or abbreviation for a function. If it's referring to a logarithmic function, it might be:

$\int \left( \frac{\ln(x)}{5} - x^3 + x \right) \, dx$

Please confirm or clarify the expression, and I can help you with the integration.