Question

Difficulty: MediumSurds and Rationalization of Denominators

If x+3x3=2\frac{\sqrt{x} + \sqrt{3}}{\sqrt{x} - \sqrt{3}} = 2, find the value of xx.

Answer: 27

Answer

The value of xx is 27.
Cross-multiplying yields x+3=2x23\sqrt{x} + \sqrt{3} = 2\sqrt{x} - 2\sqrt{3}. Rearranging terms gives x=33\sqrt{x} = 3\sqrt{3}. Squaring both sides produces x=32×3=27x = 3^2 \times 3 = 27.

Step-by-Step Solution

1
Multiply both sides by the denominator (x3)(\sqrt{x} - \sqrt{3})
x+3=2(x3)\sqrt{x} + \sqrt{3} = 2(\sqrt{x} - \sqrt{3})
Clear the rational surd expression to form a linear relation in terms of radicals
2
Expand the terms and isolate x\sqrt{x}
x=33\sqrt{x} = 3\sqrt{3}
Group terms involving x\sqrt{x} on one side and constant surds on the other side
3
Square both sides of the simplified equation
x=(33)2=9×3=27x = (3\sqrt{3})^2 = 9 \times 3 = 27
Eliminate the radical over xx to obtain the integer solution

Key Concept

Solving algebraic surd equations using rationalization concepts and properties of radicals
Estimated Time:1m 30s
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