Find the derivative of...

$\displaystyle 10x^9-6x^4+5/x^3-8x^6-10/x^6$

for this I got the following...(am I right?)

$\displaystyle -90x^8-48x^5-24x^3-12/x^4+60/x^7$

my next questions is find the derivative of...

$\displaystyle x^3/8x^8-7x^5+1$

for this i decided I need to use the quotient rule? (am i right in doing so?)

after doing the quotient rule I got this...(am I right?)

$\displaystyle dy/dx=8x^8-7x^5+1*3x^2-x^3*64x^7-35x^4/(8x^8-7x^5+1)^2$

thanks