please help me, question on finding the 2nd derivative of this equation

Question

anonymous · Answer

whtas the equation

anonymous · Answer

this is the question and my attempts

anonymous · Answer

im sorry but i have no clue

anonymous · Answer

is the question $$y = (9x ^{7} +x)*(x ^{3} -2) $$ ?????
and you want the 2nd derivative of it right?

anonymous · Answer

@genilson1986 indeed :)

anonymous · Answer

I'll try it here.. but I just see that on your 1.jpg the u' is wrong.. you put u' = 63x⁶ 
and the right one would be u'= 63x⁶ + 1

anonymous · Answer

ok thanks i'll try it again but will you try it aswell please because i think i'm making more mistakes than that.. i'm not sure...

anonymous · Answer

$$f"(x) = 810x ^{8} - 756x ^{5} +12x ^{2}$$
Thats what I've found

anonymous · Answer

$$u'= 63x ^{6} + 1$$
$$v'= 3x ^{2}$$
$$u'*v + u*v'= (63x ^{6} +1 )*(x ^{3} -2) + (9x ^{7}+x)*(3x ^{2})$$
$$90x ^{9} -126x ^{6} +4x ^{3} -2$$

anonymous · Answer

thats the first derivative

anonymous · Answer

yeah that's right i have the answer in the back of my book but how come i got $$810^{8}+12x-756^{5}-2$$ ?

anonymous · Answer

for the first derivative i took out the two so i wrote |dw:1413480765555:dw|