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Find all real roots

j(x)=32x^10-33x^5+1
I understand this part of the working out:
32(x⁵)²-33(x⁵)+1
But I don't understand how they did this part of the working out: (32x⁵-1x⁵-1)=0
X⁵=1/32 or X=1/2
Can someone explain pls
Reply 1
Original post by Bird1234
j(x)=32x^10-33x^5+1
I understand this part of the working out:
32(x⁵)²-33(x⁵)+1
But I don't understand how they did this part of the working out: (32x⁵-1x⁵-1)=0
X⁵=1/32 or X=1/2
Can someone explain pls


Its a hidden quadratic to get the values for x^5 (youve missed a couple of brakets out in your factorization) so
(32x⁵-1)(x⁵-1)=0
Then its just looking at each factor and reasoning its zero as usual and then take the 5th root.
(edited 6 months ago)
Reply 2
Original post by mqb2766
Its a hidden quadratic to get the values for x^5 (youve missed a couple of brakets out in your factorization) so
(32x⁵-1)(x⁵-1)=0
Then its just looking at each factor and reasoning its zero as usual and then take the 5th root.

OK thank you but how did u get the -1 in both brackets
Reply 3
Original post by Bird1234
OK thank you but how did u get the -1 in both brackets


Thought you said youd understood it. You just factorise the quadratic
32z^2 - 33z + 1
where z=x^5
Reply 4
Original post by mqb2766
Thought you said youd understood it. You just factorise the quadratic
32z^2 - 33z + 1
where z=x^5

I get that part but I'm confused on how u actually factorise it
Reply 5
Original post by Bird1234
I get that part but I'm confused on how u actually factorise it


If all else fails, just use the quadratic formula, but why not expand the above and see how it matches.
Reply 6
Original post by mqb2766
If all else fails, just use the quadratic formula, but why not expand the above and see how it matches.

OK thanks

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