Hi how do I factor 7x-35y^2
This is the difference between two squares:
$\displaystyle a^2-b^2$
This factors as $\displaystyle a^2-b^2=(a+b)(a-b)$
In your problem, we have $\displaystyle 7x-35y^2$
Thus, $\displaystyle a=\sqrt{7x}$ and $\displaystyle b=\sqrt{35}y$
Plug this into the formula I gave you and see what you get.
Does this make sense?
--Chris