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## Question

secondary 2 | Maths

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Please help to answer question b). Thanks in advance!

308² + 307² - 306² - 305²

= 308² - 306² + 307² - 305²

= (308 - 306)(308 + 306) + (307 - 305)(307 + 305)

= 2 x 614 + 2 x 612

= 2 x (614 + 612)

= 2 x 1226

= 2452

(a + b)² = a² + 2ab + b²

308² + 307² - 306² - 305²

= (306 + 2)² - 306² + (305 + 2)² - 305²

= 306² + 2(2)(306) + 2² - 306² + 305² + 2(2)(305) + 2² - 305²

= 1224 + 4 + 1220 + 4

= 2452

Mirandi, you can attempt this third option on your own.

(a - b)² = a² - 2ab + b²

308² + 307² - 306² - 305²

= 308² - (308 - 2)² + 307² - (307 - 2)²

= ...

=...

= 2452

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