Factorise completely x³ - 4x?
2008-11-22 9:14 am
I cannot complete this question. Could someone explain to me how to it, please?
回答 (6)
2008-11-22 9:18 am
✔ 最佳答案
x³ - 4x= x(x²-4)
= x(x²-2²)
= x(x+2)(x-2)
2008-11-22 5:35 pm
This can be solved by 2 ways. The first way is by taking x as a common factor, then:
x(x^2-4)
then factorize a^2 - b^2 = (a+b)(a-b)
x(x-2)(x+2).
the other way is by taking it as a polynomial of 3rd degree,
Take 2 as a root and by euclidean division ( long division) you wil have 0 and -2 next to 2
x(x^2-4)
then factorize a^2 - b^2 = (a+b)(a-b)
x(x-2)(x+2).
the other way is by taking it as a polynomial of 3rd degree,
Take 2 as a root and by euclidean division ( long division) you wil have 0 and -2 next to 2
2008-11-22 5:27 pm
x³ - 4x
= x(x^2 - 4) ==> Remove their Highest Common Multiples
= x(x^2 - 2^2) ==> Take their common powers. (2^2=4)
= x [(x-2)^2] ==> Open up the brackets...
= (x)(x-2)(x-2) ==> Here's the answer!
= x(x^2 - 4) ==> Remove their Highest Common Multiples
= x(x^2 - 2^2) ==> Take their common powers. (2^2=4)
= x [(x-2)^2] ==> Open up the brackets...
= (x)(x-2)(x-2) ==> Here's the answer!
2008-11-22 5:25 pm
Take out the common factor (x)
x(x^2-4)
Now its simply a difference of perfect square (DOPS)
Square root of 4 is 2
x(x-2)(x+2)
x(x^2-4)
Now its simply a difference of perfect square (DOPS)
Square root of 4 is 2
x(x-2)(x+2)
2008-11-22 5:35 pm
x(x+2)(x-2)
2008-11-22 11:29 pm
a^2 - b^2 = (a + b)(a - b)
x^3 - 4x
= x(x^2 - 4)
= x(x^2 - 2^2)
= x(x + 2)(x - 2)
x^3 - 4x
= x(x^2 - 4)
= x(x^2 - 2^2)
= x(x + 2)(x - 2)
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