Algebra II : Mathematical Relationships and Basic Graphs

Study concepts, example questions & explanations for Algebra II

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Example Questions

Example Question #51 : Multiplying And Dividing Factorials

\displaystyle \frac{2!}{13!}\div \frac{3!}{15!}

Possible Answers:

\displaystyle 20

\displaystyle 218

\displaystyle 70

\displaystyle \frac{3}{105}

\displaystyle \frac{1}{56}

Correct answer:

\displaystyle 70

Explanation:

Simplify the factorials in each fraction by canceling common factors in the numerator and denominator. It can help to write it in expanded form.

\displaystyle \frac{2!}{13!}\div \frac{3!}{15!}

\displaystyle \frac{2\cdot 1}{13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1}\div \frac{3\cdot 2\cdot 1}{15\cdot 14\cdot13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1 }

\displaystyle \frac{1}{13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3}\div \frac{1}{15\cdot 14\cdot13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4}

Since it is division of fractions change the division sign to multiplication and flip the second fraction

\displaystyle \frac{1}{13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3}\cdot \frac{15\cdot 14\cdot13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4}{1}

\displaystyle \frac{15\cdot 14\cdot13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4}{13\cdot 12\cdot 11\cdot 10\cdot 9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3}

\displaystyle \frac{15\cdot 14}{3}

\displaystyle \frac{210}{3}

\displaystyle 70

Example Question #51 : Multiplying And Dividing Factorials

\displaystyle \frac{8!\cdot 7!\cdot 3!}{9!\cdot 7!}

Possible Answers:

\displaystyle \frac{1}{9}

\displaystyle 9

\displaystyle 30

\displaystyle \frac{2}{3}

\displaystyle \frac{1}{24}

Correct answer:

\displaystyle \frac{2}{3}

Explanation:

Simplify the factorials in the fraction by canceling common factors in the numerator and denominator. It can help to write it in expanded form, but I would suggest cancelling out the 7! in the numerator and denominator first.

\displaystyle \frac{8!\cdot 7!\cdot 3!}{9!\cdot 7!}

\displaystyle \frac{8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1\cdot 3\cdot 2\cdot 1}{9\cdot 8\cdot 7\cdot 6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1}

\displaystyle \frac{3\cdot 2\cdot 1}{9}

\displaystyle \frac{6}{9}

Then reduce the fraction to lowest terms

\displaystyle \frac{2}{3}

Example Question #58 : Factorials

\displaystyle \frac{4!}{6!}\cdot \frac{7!}{2!}\cdot 2!

Possible Answers:

\displaystyle 21

\displaystyle 112

\displaystyle 28

\displaystyle 168

\displaystyle \frac{1}{1080}

Correct answer:

\displaystyle 168

Explanation:

Simplify the factorials in the fraction by canceling common factors in the numerator and denominator. It can help to write it in expanded form.

\displaystyle \frac{4!}{6!}\cdot \frac{7!}{2!}\cdot 2!

\displaystyle \frac{4\cdot 3\cdot 2\cdot 1}{6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1}\cdot \frac{7\cdot 6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1}{2\cdot 1}\cdot 2\cdot 1

\displaystyle \frac{1}{6\cdot 5}\cdot \frac{7\cdot 6\cdot 5\cdot 4\cdot 3}{1}\cdot 2\cdot 1

Combine each of the fractions into one fraction.

\displaystyle \frac{7\cdot 6\cdot 5\cdot 4\cdot 3\cdot 2\cdot 1}{6\cdot 5}

\displaystyle \frac{7\cdot 4\cdot 3\cdot 2\cdot 1}{1}

\displaystyle \frac{168}{1}

\displaystyle 168

Example Question #52 : Factorials

Divide the factorials:  \displaystyle \frac{3!}{5!} \div \frac{5!}{3!}

Possible Answers:

\displaystyle \frac{1}{225}

\displaystyle \frac{1}{5}

\displaystyle 1

\displaystyle \frac{1}{400}

Correct answer:

\displaystyle \frac{1}{400}

Explanation:

Dividing by a fraction is the same as multiplying by the reciprocal of the fraction.

\displaystyle \frac{3!}{5!} \div \frac{5!}{3!}=\frac{3!}{5!}\times \frac{3!}{5!}

Write out the terms of the factorials.

\displaystyle \frac{3!}{5!}\times \frac{3!}{5!}= \frac{3\times 2\times 1}{5\times 4\times 3\times 2\times 1}\times \frac{3\times 2\times 1}{5\times 4\times 3\times 2\times 1}

Cancel all common terms.

\displaystyle \frac{1}{5\times 4}\times\frac{1}{5\times 4} = \frac{1}{20}\times \frac{1}{20} = \frac{1}{400}

The answer is:  \displaystyle \frac{1}{400}

Example Question #51 : Factorials

Divide the factorials:   \displaystyle \frac{2(4+1)!}{3!(2+3)!}

Possible Answers:

\displaystyle \frac{1}{720}

\displaystyle \frac{504}{505}

\displaystyle 504

\displaystyle 432

\displaystyle \frac{1}{3}

Correct answer:

\displaystyle \frac{1}{3}

Explanation:

Evaluate the terms in parentheses first.  Do not distribute the integer through the parentheses or this will change the value of the factorial!

\displaystyle \frac{2(4+1)!}{3!(2+3)!} =\frac{2(5)!}{3!(5)!}

The common terms in the numerator and denominator can be simplified.

\displaystyle \frac{2}{3!} = \frac{2}{3 \times 2\times 1} = \frac{1}{3}

The answer is:  \displaystyle \frac{1}{3}

Example Question #52 : Multiplying And Dividing Factorials

Divide the factorials:  \displaystyle \frac{3(2+3!)}{1-4!}

Possible Answers:

\displaystyle -\frac{87}{23}

\displaystyle -\frac{24}{23}

\displaystyle 0

\displaystyle -\frac{360}{23}

Correct answer:

\displaystyle -\frac{24}{23}

Explanation:

Simplify the factorials first.

\displaystyle 3! = 3\cdot2\cdot1 = 6

\displaystyle 4! = 4\cdot3\cdot2\cdot1 = 24

Replace the values back into the problem.

\displaystyle \frac{3(2+3!)}{1-4!} = \frac{3(2+6)}{1-24} = \frac{24}{-23}

The answer is:  \displaystyle -\frac{24}{23}

Example Question #51 : Multiplying And Dividing Factorials

Simplify:  \displaystyle \frac{2(3!+4)}{(2+2)!}

Possible Answers:

\displaystyle \frac{91}{3}

\displaystyle \frac{10}{3}

\displaystyle \frac{5}{6}

\displaystyle 5

\displaystyle \frac{181}{6}

Correct answer:

\displaystyle \frac{5}{6}

Explanation:

Simplify the denominator.

\displaystyle \frac{2(3!+4)}{(2+2)!}=\frac{2(3!+4)}{4!}

Rewrite each factorial in the given fraction.  Do not distribute the two through the quantity or this will change the value of the factorial.

\displaystyle \frac{2(3!+4)}{4!} =\frac{2([3\times 2\times 1]+4)}{[4\times3\times 2\times 1] } = \frac{2(6+4)}{24}=\frac{2(10)}{24}=\frac{20}{24}

Reduce this fraction.

The answer is:  \displaystyle \frac{5}{6}

Example Question #61 : Multiplying And Dividing Factorials

Divide the factorials:  \displaystyle \frac{2(3+2)!}{3!}

Possible Answers:

\displaystyle 604800

\displaystyle 40

\displaystyle 24

\displaystyle 30

\displaystyle 120

Correct answer:

\displaystyle 40

Explanation:

To simplify this, we will need to evaluate the parentheses first.  Do not distribute the integer two into the binomial, or the factorial value will change.

\displaystyle \frac{2(3+2)!}{3!}=\frac{2(5)!}{3!}

Expand the factorials.

\displaystyle \frac{2(5)!}{3!} = \frac{2(5\cdot 4\cdot 3\cdot 2\cdot 1)}{3\cdot 2\cdot 1}

Simplify the top and bottom terms.

\displaystyle 2(5\cdot 4) = 40

The answer is:  \displaystyle 40

Example Question #2871 : Algebra Ii

Multiply:  \displaystyle (3!)(3+2)!(\frac{1}{4!})

Possible Answers:

\displaystyle 60

\displaystyle 15

\displaystyle 40

\displaystyle 120

\displaystyle 30

Correct answer:

\displaystyle 30

Explanation:

Simplify the inner parentheses and expand the factorials.

\displaystyle (3!)(3+2)!(\frac{1}{4!}) = (3\times 2\times 1)(5)!(\frac{1}{4 \times 3\times 2\times 1})

Cancel out common terms.

\displaystyle (5\times 4\times 3\times 2\times 1)(\frac{1}{4}) = 5\times 3\times 2\times 1

The answer is:  \displaystyle 30

Example Question #61 : Factorials

Multiply:  \displaystyle \frac{2!}{3!}\cdot \frac{4!}{6!}

Possible Answers:

\displaystyle \frac{1}{90}

\displaystyle \frac{2}{15}

\displaystyle \frac{2}{15}

\displaystyle \frac{1}{60}

\displaystyle \frac{1}{30}

Correct answer:

\displaystyle \frac{1}{90}

Explanation:

In order to solve this, we will need to expand all the factorials.

\displaystyle \frac{2!}{3!}\cdot \frac{4!}{6!} = \frac{2\times1}{3\times2\times1}\cdot \frac{4\times3\times2\times1}{6\times5\times4\times3\times2\times1 }

Cancel all the common terms and write the remaining numbers.

\displaystyle \frac{1}{3 }\cdot \frac{1}{30} = \frac{1}{90}

The answer is:  \displaystyle \frac{1}{90}

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