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secondary 3 | A Maths
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Rachel
Rachel

secondary 3 chevron_right A Maths chevron_right Singapore

please help me with part 2 :-)

Date Posted: 5 years ago
Views: 298
J
J
5 years ago
a + b√3 = (5 + 2√3)²/(2 + √3)

a + b√3 = (25 + 20√3 + 12)/(2 +√3)

a + b√3 = (37 + 20√3)/(2 + √3) x (2 - √3)/(2 - √3)

a + b√3 = (37 + 20√3)(2 - √3)/(2² - (√3)²)

a + b√3 = (74 - 37√3 + 40√3 - 60)/(1)

a + b√3 = 14 + 3√3

Comparing coefficients,

a = 14
b = 3

Idea here is to bring over the denominator 5 + 2√3 to the other side.

Then rationalise the denominator 2 +√3


Some steps were skipped/simplified

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
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Hi Rachel! Here are my workings for the two questions