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Given that x=412+527–375+300x = 4\sqrt{12} + 5\sqrt{27 }– 3\sqrt{75 }+ \sqrt{300}x=412​+527​–375​+300​​ and y = (2+3)(2–3).(2 + \sqrt3)(2 – \sqrt3).(2
Question

Given that x=412+527375+300x = 4\sqrt{12} + 5\sqrt{27 }– 3\sqrt{75 }+ \sqrt{300}​ and y = (2+3)(23).(2 + \sqrt3)(2 – \sqrt3).​ If xy=a+b3,\frac x y = a + b\sqrt3,​ then what is the value of (a + 2b)?

A.

30

B.

36

C.

40

D.

24

Correct option is B

Given:x=412+527375+300y=(2+3)(23)and xy=a+b3Required value =a+2bConcept Used:Simplification of surds and rationalizationFormula Used:mn=mn(a+b)(ab)=a2b2Solution:x=412+527375+300=4(23)+5(33)3(53)+103=83+153153+103=183y=(2+3)(23)=43=1xy=1831=183Comparing with a+b3:a=0,b=18a+2b=0+2(18)=36Final Answer:36\textbf{Given:} \\x = 4\sqrt{12} + 5\sqrt{27} - 3\sqrt{75} + \sqrt{300} \\y = (2 + \sqrt{3})(2 - \sqrt{3}) \\\text{and } \frac{x}{y} = a + b\sqrt{3} \\\text{Required value } = a + 2b \\\textbf{Concept Used:} \\\text{Simplification of surds and rationalization} \\\textbf{Formula Used:} \\\sqrt{mn} = \sqrt{m}\sqrt{n} \\(a + b)(a - b) = a^2 - b^2 \\\textbf{Solution:} \\x = 4\sqrt{12} + 5\sqrt{27} - 3\sqrt{75} + \sqrt{300} \\= 4(2\sqrt{3}) + 5(3\sqrt{3}) - 3(5\sqrt{3}) + 10\sqrt{3} \\= 8\sqrt{3} + 15\sqrt{3} - 15\sqrt{3} + 10\sqrt{3} \\= 18\sqrt{3} \\y = (2 + \sqrt{3})(2 - \sqrt{3}) \\= 4 - 3 \\= 1 \\\frac{x}{y} = \frac{18\sqrt{3}}{1} \\= 18\sqrt{3} \\\text{Comparing with } a + b\sqrt{3}: \\a = 0,\quad b = 18 \\a + 2b = 0 + 2(18) \\= 36 \\\textbf{Final Answer:} \\36​​

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