Using identities find the value of (891)sq?
回答 (2)
2016-04-27 6:17 pm
✔ 最佳答案
Hello Aryan, let us try this way. Okay....891 = 900 - 9 = 9(100-1)
Now 891^2 = (9^2) (100-1)^2
===> 81 * (10000-200+1) = 81 * 9801 =
Now it is easy
2016-04-27 5:51 pm
Identities :
(x + y)² = x² + 2xy + y²
(x - y)² = x² - 2xy + y²
891²
= (890 + 1)²
= 890² + 2(890) + 1²
= (900 - 10)² + 1780 + 1
= 900² - 2(900)(10) + 10² + 1781
= 810000 - 18000 + 100 + 1781
= 793881
(x + y)² = x² + 2xy + y²
(x - y)² = x² - 2xy + y²
891²
= (890 + 1)²
= 890² + 2(890) + 1²
= (900 - 10)² + 1780 + 1
= 900² - 2(900)(10) + 10² + 1781
= 810000 - 18000 + 100 + 1781
= 793881
收錄日期: 2021-04-18 14:49:56
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