deleted question.
Simple u-substitution :) but there is a little trick in the middle of it.
\[\Large\rm \color{royalblue}{u=1+2x}\]Subtracting 1 from each side,\[\Large\rm u-1=2x\]Divide by 2,\[\Large\rm \color{orangered}{\frac{1}{2}(u-1)=x}\] Do you understand WHY I did that? The blue let's us take care of the denominator. The orange let's us take care of the numerator.
And you will also need your dx I suppose.\[\Large\rm du=2dx\qquad\to\qquad \frac{1}{2}du=dx\]
The orange :o
Woops, an extra 1/2 from your du as well, yes?
Yah there we go \c:/ The whole trick was, we needed to get rid of the addition under the root, so we could divide it easier.
\[\LARGE \int\limits\limits_{ }^{ }\frac{\frac{1}{2}(u-1)}{\sqrt{u}}~\left(\frac{1}{2}du\right)\]
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