Finding the volume of a solid by rotating two curves about the $y$-axis Find the volume of the solid obtained by rotating the region bounded by the given curves about the $y$-axis.
$$y=56x−7x^2 \mbox { and }y=0$$ 
My issue with this question is that I am having trouble turning the equation, $y=56x−7x^2$, in terms of $y$. I understand that by doing that, I can proceed with the integration...
Perhaps there is another method to do this without having to turn it in terms of $y$?
Thanks

Following the advice from John Habert we can use the cylindrical shell method. 
$V = 2 \pi \int_{a}^{b} x f(x) dx $
It is very helpful to draw the picture and a representative cylindrical shell
To get the x limits we solve $56x - 7x^2 = 0$
Where lower x limit , $a = 0$
Upper x limit , $b = 8$
Height of a representative shell . $f(x) = 56x - 7x^2$
$V = 2 \pi \int_{0}^{8} x(56x - 7x^2) dx$
Simplify , then integrate. 
