Soru

Zorluk: Çok zorSurds and Rationalization of Denominators

Given that x+2+x2x+2x2=3\frac{\sqrt{x + 2} + \sqrt{x - 2}}{\sqrt{x + 2} - \sqrt{x - 2}} = 3, what is the value of xx?

  1. 103\frac{10}{3}Cevap
  2. B
    66
  3. C
    52\frac{5}{2}
  4. D
    83\frac{8}{3}

Cevap

The value of xx is 103\frac{10}{3}.
The correct solution is found by cross-multiplying the equation to get x+2+x2=3x+23x2\sqrt{x + 2} + \sqrt{x - 2} = 3\sqrt{x + 2} - 3\sqrt{x - 2}. Grouping similar surd terms gives 4x2=2x+24\sqrt{x - 2} = 2\sqrt{x + 2}, which simplifies to 2x2=x+22\sqrt{x - 2} = \sqrt{x + 2}. Squaring both sides yields 4(x2)=x+24(x - 2) = x + 2, simplifying to 4x8=x+24x - 8 = x + 2, which gives 3x=103x = 10 and x=103x = \frac{10}{3}.

Adım Adım Çözüm

1
Cross-multiply to clear the denominator
x+2+x2=3(x+2x2)\sqrt{x + 2} + \sqrt{x - 2} = 3(\sqrt{x + 2} - \sqrt{x - 2})
Clear the fraction to group like radical terms on opposite sides.
2
Rearrange and combine like terms
4x2=2x+24\sqrt{x - 2} = 2\sqrt{x + 2}, which simplifies to 2x2=x+22\sqrt{x - 2} = \sqrt{x + 2}
Isolate the radical expressions.
3
Square both sides of the equation
(2x2)2=(x+2)2    4(x2)=x+2(2\sqrt{x - 2})^2 = (\sqrt{x + 2})^2 \implies 4(x - 2) = x + 2
Eliminate radicals by squaring both sides, ensuring the coefficient 22 is squared to 44.
4
Solve the linear equation for xx
4x8=x+2    3x=10    x=1034x - 8 = x + 2 \implies 3x = 10 \implies x = \frac{10}{3}
Isolate xx to find the final value.

Anahtar Kavram

Solving Radical and Surd Equations
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