Could someone please help me, I do not understand how the author of my text book gets from one point to another. Here is the problem worked out, after the problem I will explain which part I don't understand.(adsbygoogle = window.adsbygoogle || []).push({});

[tex]f(x)=x(x-4)^3[/tex]

[tex]f'(x)=x[3(x-4)^2]+(x-4)^3[/tex]

[tex]=(x-4)^2(4x-4)[/tex]

I do not understand how the author gets from here:

[tex]f'(x)=x[3(x-4)^2]+(x-4)^3[/tex]

to here:

[tex]=(x-4)^2(4x-4)[/tex]

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# Product and Chain Rule

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