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113: Operations on Radicals - Rationalize Binomial
By Marjorie Brewer
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Bell Assignment: multiply
Question 1
1.
(2-3\sqrt{6})(-5-\sqrt{6})
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Question 2
2.
(5+\sqrt{7})(5-\sqrt{7})
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Notes L6-5c: Rationalize Binomial Denominators
note: (a+b)(a-b) are called
conjugates
. Like
[2]
, when conjugates are multipled together, the middle terms cancel.
Since we are working with square roots, we can use conjugates to eliminate the root.
Question 3
3.
Question 4
4.
Multiply together 9-\sqrt{5} and its conjugate.
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Question 5
5.
Question 6
6.
Multiply together -3+\sqrt{11} and its conjugate.
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Mathematicians do not like radicals in denominators. So, we rationalize by multiplying by the conjugate.
Question 7
7.
Question 8
8.
Question 9
9.
Rationalize: \LARGE \frac{-2}{-8+\sqrt{6}}
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Question 10
10.
Rationalize: \LARGE \frac{-1}{-2-\sqrt{7}}
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Question 11
11.
Rationalize: \LARGE \frac{6}{-8-\sqrt{11}}
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Question 12
12.
Rationalize: \LARGE \frac{-2}{-4+\sqrt{14}}
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Question 13
13.
Finish first 14 sections of DelatMath.
Which is the conjugate of 9-\sqrt{5}?
\sqrt{5}-9
9-\sqrt{5}
9+\sqrt{5}
Which is the conjugate of -3+\sqrt{11}?
\sqrt{11}-3
\sqrt{11}+3
-3-\sqrt{11}
-3+\sqrt{11}
To rationalize \LARGE \frac{-2}{-8+\sqrt{6}}
you would:
Show that you are multipling by the conjugate (on the top and bottom).
Distibute (by foiling) in both the top and bottom.
Reduce if possible.
Find the conjugate.
Simplify both the numerator and denominator.
To rationalize \LARGE \frac{-2}{-8+\sqrt{6}}
Which step is correct?
\LARGE \frac{-2 (-8+\sqrt{6})}{(-8+\sqrt{6})(-8+\sqrt{6})}
\LARGE \frac{-2 (-8-\sqrt{6})}{(-8+\sqrt{6})(-8-\sqrt{6})}
\LARGE \frac{-2 (-8+\sqrt{6})}{(-8+\sqrt{6})(-8-\sqrt{6})}
\LARGE \frac{-2 (-8-\sqrt{6})}{(-8+\sqrt{6})(-8+\sqrt{6})}
Choose all that are true
I am confident in this lesson.
I would like some assistance.
I can find the conjugate.
I can rationalize binomial denominators.