Find the derivative of Y=5x(2x - 4)^4 X=3

I did this manually and got 320 , but then my TI-89 derivative Calculator got 960. Can anyone run me through it please, thanks! Start of with Chain rule, right?

Question

Find the derivative of Y=5x(2x - 4)^4 X=3

I did this manually and got 320 , but then my TI-89 derivative Calculator got 960. Can anyone run me through it please, thanks!  Start of with Chain rule, right?

zarkon · Answer

the way you typed the equation...neither 320 nor 960 are correct.

anonymous · Answer

i get 1040...

anonymous · Answer

http://www.wolframalpha.com/input/?i=derivative+5x%282x+-+4%29%5E4%2Cx%3D3

anonymous · Answer

you can type here just derivative 5x(2x - 4)^4 and it will show you steps