Pearson Algebra 2 Common Core, 2011
PA
Pearson Algebra 2 Common Core, 2011 View details
End-of-Course Assessment

Exercise 5 Page 964

To rationalize a fraction with a binomial denominator, multiply the numerator and denominator of the fraction by the conjugate of the denominator.

D

Practice makes perfect
We want to find a simpler form of the given fraction with a binomial denominator. To do it, we will rationalize the fraction by multiplying the numerator and denominator of the fraction by the conjugate of the denominator. We find the conjugate by changing the sign of the second term of the expression.
Binomial Conjugate
a + b a - b
a - b a + b
In this case, the conjugate of the denominator is 3+sqrt(2).
sqrt(5)/3-sqrt(2)
sqrt(5)(3+sqrt(2))/(3-sqrt(2))(3+sqrt(2))

(a-b)(a+b)=a^2-b^2

sqrt(5)(3+sqrt(2))/9-(sqrt(2))^2
sqrt(5)(3+sqrt(2))/9-2
sqrt(5)(3+sqrt(2))/7
3sqrt(5)+sqrt(2)sqrt(5)/7
3sqrt(5)+sqrt(2* 5)/7
3sqrt(5)+sqrt(10)/7
This corresponds to option D.