Math  /  Algebra

QuestionWhich is the rationalized form of the expression xx+7\frac{\sqrt{x}}{\sqrt{x}+\sqrt{7}} ? a. x7xx7\frac{x-\sqrt{7 x}}{x-7} c. x+7xx7\frac{x+\sqrt{7 x}}{x-7} b. 7x7\frac{\sqrt{7 x}}{7} d. xx+7\frac{x}{x+7}

Studdy Solution

STEP 1

1. We are given an expression with a radical in the denominator.
2. The goal is to rationalize the denominator.
3. Rationalizing involves eliminating the square root from the denominator.

STEP 2

1. Multiply the numerator and the denominator by the conjugate of the denominator.
2. Simplify the resulting expression.

STEP 3

Identify the conjugate of the denominator x+7\sqrt{x} + \sqrt{7}. The conjugate is x7\sqrt{x} - \sqrt{7}.
Multiply both the numerator and the denominator by this conjugate:
xx+7×x7x7\frac{\sqrt{x}}{\sqrt{x}+\sqrt{7}} \times \frac{\sqrt{x} - \sqrt{7}}{\sqrt{x} - \sqrt{7}}

STEP 4

Simplify the numerator:
x×(x7)=x7x\sqrt{x} \times (\sqrt{x} - \sqrt{7}) = x - \sqrt{7x}

STEP 5

Simplify the denominator using the difference of squares formula:
(x+7)(x7)=(x)2(7)2=x7(\sqrt{x} + \sqrt{7})(\sqrt{x} - \sqrt{7}) = (\sqrt{x})^2 - (\sqrt{7})^2 = x - 7

STEP 6

Combine the simplified numerator and denominator:
x7xx7\frac{x - \sqrt{7x}}{x - 7}
This is the rationalized form of the expression.
The rationalized form of the expression is:
x7xx7 \boxed{\frac{x - \sqrt{7x}}{x - 7}}
This corresponds to option a.

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