OK, the professor did this problem for us as an example and i got lost somewhere in between. the problem was: find the critical points(adsbygoogle = window.adsbygoogle || []).push({});

f(x)= x^(4/5)*(x-4)^2

then he used the product rule to get

f '(x)= 4/5 x^(-1/5) *(x-4)^2 + x^(4/5) * 2(x-4) = 0

THEN, the part that threw me off was the next part where he said multiply both sides by 1/5....what did he mean by that? after that you get

4/5 (x-4)^2 + 2x(x-4) = 0 and so on...

my question is how and what did he do to get rid of the x^(-1/5) and the x^(4/5)???

Any help would be greatly appreciated

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# Homework Help: Max and Min Values

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