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1. Solve the equation x^6 + 26x^3 -27=0
i substituted x^6 for x^2,
so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
2. You're on the right track. You can factorise by finding two numbers whose sum is and whose product is .
3. (Original post by Chelsea12345)
Solve the equation x^6 + 26x^3 -27=0
i substituted x^6 for x^2,
so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
You can't find two numbers that multiply to give -27 and add to give 26 ?????
By considering every positive integer starting at 1, Systematically make a list of factor pairs
1 and -27
3 and -9
9 and -3
Etc

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4. (Original post by Chelsea12345)
Solve the equation x^6 + 26x^3 -27=0
i substituted x^6 for x^2,
so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
It can be factorised. I don't really want to give you the answer, but 27 and 1.
5. (Original post by Chelsea12345)
Solve the equation x^6 + 26x^3 -27=0
i substituted x^6 for x^2,
so i'm trying to factorise x^2+26x-27=0?? i cant seem to factorise it.
You know, completing the square is always an option. You don't always have to give up just because you can't spot the shortcut.
6. if you can't spot the factors you could complete the square & solve ?
7. (Original post by RDKGames)
You know, completing the square is always an option. You don't always have to give up just because you can't spot the shortcut.
i wasn't aware that factorising is a shortcut and even so, i've been repeatedly trying to factorise the equation using different numbers for a quite a while before i posted the question. The thought of completing the score hasn't crossed my mind but implying that i'm giving up on the question is uncalled for.
8. for this example it would be quite hard to use the formula to solve, but completing the square is not too bad.
9. (Original post by emduck)
It can be factorised. I don't really want to give you the answer, but 27 and 1.
correction 27 and -1

(Original post by gdunne42)
You can't find two numbers that multiply to give -27 and add to give 26 ?????

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10. (Original post by Emz99)
correction 27 and -1
I know. (x-1)(x+27)=0 x=1 or x=-27 but I just gave the factors that made up 27, I assumed they'd be able to work out the rest. I guess I should've probably said 27 and -1

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