Here we will show an alternative way to get from a general partial fraction with a quadratic factor to simpler forms.
The starting point is again the idea that we can use x in the
numerator to set up a quadratic substitution, but this time we do not delay
it for after getting rid fo the linear part. But if we want to do such a
substitution right away, then we need to create the expression
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We get

Now we can easily integrate the first integral using the obvious quadratic substitution.
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The second integral in decomposition above had only a constant in its numerator, se it is possible to transform it using completion of square into an integral leading to asc tangent, just like in the recommended algorithm.