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secondary 2 | Maths
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Anyone can contribute an answer, even non-tutors.
Please help to answer question b). Thanks in advance!
Date Posted: 5 years ago
Views: 307
a² - b² = (a + b)(a - b)
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
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
Or
(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
(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
Or (308^2 - 305^2) + (307^2 - 306^2).
Mirandi, you can attempt this third option on your own.
Mirandi, you can attempt this third option on your own.
And one more option :
(a - b)² = a² - 2ab + b²
308² + 307² - 306² - 305²
= 308² - (308 - 2)² + 307² - (307 - 2)²
= ...
=...
= 2452
(a - b)² = a² - 2ab + b²
308² + 307² - 306² - 305²
= 308² - (308 - 2)² + 307² - (307 - 2)²
= ...
=...
= 2452
See 1 Answer
done
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clear
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tip: need to look for similarities between part a and b
Date Posted:
5 years ago
Thanks!
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