Advanced Factorization

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jeremychung

1)Factorize x^4-100x^2+324

2)Factorize a^12-1

Dekker

1) make x²=p.
with D=b²-4ac and p=(-b+/-sqrt(D))/2a
Makes p=

so x= the square root of the answer above, which is of course wrong...

2) a^12-1 is equal to 0
    a^12=1

a = 1 or a = -1

(unless you want ten other imaginary solutions =P)

jeremychung

Do you know the definition of factorization?If you don't understand more,I may help you more!

Dekker

oops, that´s my english!

is factorisation to get in in a shape like (x....)(x...)=0?

jeremychung

(x...)(x...)

jeremychung

Let me show the solution.

1)x^4-100x^2+324=x^4-2(18)x^2+324-100x^2+2(18)x^2

                         =(x^2-18)^2-64x^2

                         =(x^2-18)^2-(8x)^2

                         =(x^2-8x-18)(x^2+8x-18)

2)a^12-1=(a^6-1)(a^6+1)

            = (a^3-1)(a^3+1)[(a^2)^3+1]

            =(a-1)(a^2+a+1)(a+1)(a^2-a+1)(a^2+1)(a^4-a^2+1)

            =(a-1)(a+1)(a^2+1)(a^2+a+1)(a^2-a+1)(a^4-a^2+1)

Dekker

okay, that´s a bit too high 4 me!
i can only do ax²+bx+c=d and a bit x³+bx²+cx+d=0 and i´m happy with that!