2a^2b−20ab+50b−2b^3?
回答 (2)
2016-03-29 5:11 pm
2a²b - 20ab + 50b - 2b³
= 2b(a² - 10a + 25 - b²)
= 2b[(a² - 2a(5) + 5²) - b²]
= 2b[(a - 5²) - b²] ...... 因為 u² - 2uv + v² = (u - v)²
= 2b[(a - 5) + b][(a - 5) - b] ...... 因為 u² - v² = (u + v)(u - v)
= 2b(a + b - 5)(a - b - 5)
= 2b(a² - 10a + 25 - b²)
= 2b[(a² - 2a(5) + 5²) - b²]
= 2b[(a - 5²) - b²] ...... 因為 u² - 2uv + v² = (u - v)²
= 2b[(a - 5) + b][(a - 5) - b] ...... 因為 u² - v² = (u + v)(u - v)
= 2b(a + b - 5)(a - b - 5)
2016-04-10 7:48 am
2a^2b−20ab+50b−2b^3
=2b(a^2-10a+25-b^2)
=2b[(a-5)^2-b^2]
=2b(a-b-5)(a+b-5)
=2b(a^2-10a+25-b^2)
=2b[(a-5)^2-b^2]
=2b(a-b-5)(a+b-5)
收錄日期: 2021-04-18 14:39:46
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https://hk.answers.yahoo.com/question/index?qid=20160329090411AA2AlC5