Lets say i have a question, for example, $\displaystyle \int_0^5 (x^2-9)^2\;dx$

Now if i wanted to show my entire work for this question, i would start off like this:

$\displaystyle \int_0^5 (x^2-9)^2\;dx=\int_0^5 \x^4-18x^2+81;dx$

Now lets assume i want to show every single step afterwards...how do i use latex such that all my further work will start with an equal sign but IN LINE my first equal sign so such that i WOULDNT need to repeat the original question everytime (for it to align)

I hope this is understandable :P

Thanks

PS. I know this shouldn't be here...but lets face it...placing it in the right sections get little/no attention.