I'm after some help with these two equations.

My problem is factorising with equations like this, I can never tell when I'm supposed to do it!! I have the answers to these questions I just need explicit help, basically a walk through of these examples, if anyone can help I'd much appreciate it,

Thanks

ydy/dx+7x^2+7x+5=0

which satisfies y(0)=4

The Answer is:

sqrt(16-(14/3x^3 + 7x^2+10x))

and my other problem is,

dy/dx = 1+y^2/7+9x

which satisfies y(1) = 0

tan(1/9ln(|7+9x/16|))

With regards to the last answer, how does PI sometimes come out of this answer?

PS how do you write with math symbols, it looks a bit messy....