225k views
5 votes
Which of the following radical expressions is equivalent to 2/ (√32 - 5√2)?

a 1/2(√2-5)
b √(2+5)/4
c (√2-5)/4
d 2(√2+5)/14

1 Answer

5 votes

Final answer:

The given radical expression 2 / (√32 - 5√2) was simplified using rationalization. After simplification, the result did not match any of the given options, so 'None of the above' is the correct choice.

Step-by-step explanation:

The student asked which of the following radical expressions is equivalent to 2 / (√32 - 5√2).

To solve such an expression, we should rationalize the denominator.

This involves multiplying the numerator and the denominator by the conjugate of the denominator which is (√32 + 5√2).

Let's first simplify √32.

Since 32 = 16 * 2 and the square root of 16 is 4, √32 = 4√2. Our expression now looks like 2 / (4√2 - 5√2).

Combining like terms in the denominator, we get 2 / (-√2).

Multiplying both numerator and denominator by the conjugate of the denominator, we get:
(2 * (√2 + 5√2)) / ((-1)(2 - 25))
Which simplifies to (2√2 + 10√2) / 23 or 2(√2 + 5) / 23.

Comparing this with the given options, none of them match exactly, so the correct answer is None of the above.

User Daveaglick
by
7.9k points