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Question
Find the value of a and b in the following:
`(4sqrt(3))/(2 - sqrt(3)) = a + bsqrt(3)`
Sum
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Solution
We are given:
`(4sqrt(3))/(2 - sqrt(3)) = a + bsqrt(3)`
Step 1: Multiply numerator and denominator by the conjugate of the denominator:
`(4sqrt(3))/(2 - sqrt(3)) xx (2 + sqrt(3))/(2 + sqrt(3))`
= `(4sqrt(3)(2 + sqrt(3)))/((2 - sqrt(3))(2 + sqrt(3))`
Step 2: Simplify the denominator:
`(2 - sqrt(3))(2 + sqrt(3))`
= 4 – 3
= 1
So we just need to expand the numerator:
`4sqrt(3)(2 + sqrt(3))`
= `8sqrt(3) + 4 xx 3`
= `8sqrt(3) + 12`
Step 3: Rearrange:
`8sqrt(3) + 12 = 12 + 8sqrt(3)`
a = 12, b = 8
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Chapter 1: Rational and Irrational Numbers - EXERCISE 1C [Page 15]
