how do I factor out 64-8x^3?
回答 (6)
✔ 最佳答案
a³-b³ = (a-b)(a²+ab+b²)
64-8x³
= 8(8-x³)
= 8(2³-x³)
= 8(2-x)(2²+2x+x²)
= 8(2-x)(4+2x+x²)
a^3 - b^3 = (a - b)(a^2 + ab + b^2)
64 - 8x^3
= 8(8 - x^3)
= 8(2^3 - x^3)
= 8(2 - x)(2^2 + 2x + x^2)
= 8(2 - x)(4 + 2x + x^2)
both terms are divisible by "8", so you can pull it out of both. that would leave you with
8(8 - x^3)
you can factor further because of the difference of two cubes, leaving the final answer of
8(2 - x)(x^2 + 2x + 4)
(4-2x)(16+8x+4x^2)=
=64+32x+16x^2 -32x-16x^2-8x^3=
=64-8x^3
=2(2-x)(4)(4+2x+x^2)=
=8(2-x)(x^2+2x+4)
rewrite it as 4^3 - (2x)^3 = (4-2x)(16 + 8x + 4x^2)
note: a^3 - b^3 = (a-b)(a^2 + ab + b^2)
64 = 4^3
8 = 2^3
64 - 8x^3 = 4^3 - 2^3 x^3 = 4^3 - (2x)^3
Now, use the difference of cubes identity:
a^3 - b^3 = (a - b)(a^2 + ab + b^2)
a=4, b=2x
64 - 8x^3 = (4 - 2x)(16 + 8x + 4x^2)
收錄日期: 2021-05-01 11:34:42
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20081122225206AAzh5X2
檢視 Wayback Machine 備份