Math Problem Statement

Sederhanakan bentuk pecahan berikut dengan cara merasionalkan penyebutnya: (√8 - √6) / (√8 + √6)

Solution

To simplify the expression given in the image:

868+6\frac{\sqrt{8} - \sqrt{6}}{\sqrt{8} + \sqrt{6}}

using the method of rationalizing the denominator, we multiply both the numerator and the denominator by the conjugate of the denominator. The conjugate of 8+6\sqrt{8} + \sqrt{6} is 86\sqrt{8} - \sqrt{6}.

So, multiply both the numerator and denominator by 86\sqrt{8} - \sqrt{6}:

868+6×8686\frac{\sqrt{8} - \sqrt{6}}{\sqrt{8} + \sqrt{6}} \times \frac{\sqrt{8} - \sqrt{6}}{\sqrt{8} - \sqrt{6}}

This gives:

(86)2(8)2(6)2\frac{(\sqrt{8} - \sqrt{6})^2}{(\sqrt{8})^2 - (\sqrt{6})^2}

Now simplify:

  1. Numerator: (86)2=(8)2286+(6)2=8248+6=14248(\sqrt{8} - \sqrt{6})^2 = (\sqrt{8})^2 - 2\sqrt{8}\sqrt{6} + (\sqrt{6})^2 = 8 - 2\sqrt{48} + 6 = 14 - 2\sqrt{48}

Since 48=43\sqrt{48} = 4\sqrt{3}, the numerator becomes: 148314 - 8\sqrt{3}

  1. Denominator: (8)2(6)2=86=2(\sqrt{8})^2 - (\sqrt{6})^2 = 8 - 6 = 2

Now, the expression becomes: 14832\frac{14 - 8\sqrt{3}}{2}

Finally, simplify by dividing both terms in the numerator by 2: 7437 - 4\sqrt{3}

Thus, the simplified expression is:

7437 - 4\sqrt{3}

Would you like a detailed explanation of any of the steps?


Here are five related questions for further practice:

  1. How do you simplify 535+3\frac{\sqrt{5} - \sqrt{3}}{\sqrt{5} + \sqrt{3}} using rationalization?
  2. What is the conjugate of a+b\sqrt{a} + \sqrt{b}, and why is it used in rationalization?
  3. How would you rationalize 12+3\frac{1}{\sqrt{2} + \sqrt{3}}?
  4. What is the simplified result of 10210+2\frac{\sqrt{10} - \sqrt{2}}{\sqrt{10} + \sqrt{2}}?
  5. Can you apply rationalization to a denominator of the form a+bca + b\sqrt{c}? How?

Tip: When rationalizing, always multiply by the conjugate of the denominator to eliminate radicals.

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Math Problem Analysis

Mathematical Concepts

Rationalization
Simplifying Radicals
Algebra

Formulas

Conjugate multiplication formula: (a + b)(a - b) = a^2 - b^2
Rationalization of the denominator

Theorems

Conjugate theorem for radicals
Difference of squares theorem

Suitable Grade Level

Grades 10-12