J's answer to Crystal's Secondary 4 E Maths Singapore question.
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(5n + 1)² - (5n - 1)²
= (5n + 1 + (5n - 1))(5n + 1 - (5n - 1))
= (5n + 1 + 5n - 1)(5n + 1 - 5n + 1)
= (10n)(2)
= 20n
(Shown)
The property used is : a² - b² = (a + b)(a - b)
= (5n + 1 + (5n - 1))(5n + 1 - (5n - 1))
= (5n + 1 + 5n - 1)(5n + 1 - 5n + 1)
= (10n)(2)
= 20n
(Shown)
The property used is : a² - b² = (a + b)(a - b)
Date Posted:
3 years ago
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