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13.6 Binomial Theorem

Expanding a power of a binomial using coefficients from Pascal's triangle, and isolating a single term without writing them all.

Algebra and Trigonometry 2e, 13.6 Binomial Theorem

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29 exercises

Finding Binomial Coefficients

Find each binomial coefficient.

  1. ⓐ ( 5 3 ) \begin{pmatrix} 5 \\ 3 \end{pmatrix}
  2. ⓑ ( 9 2 ) \begin{pmatrix} 9 \\ 2 \end{pmatrix}
  3. ⓒ ( 9 7 ) \begin{pmatrix} 9 \\ 7 \end{pmatrix}
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13.6 Exercise 8

Find each binomial coefficient.

  1. ⓐ ( 7 3 ) \begin{pmatrix} 7 \\ 3 \end{pmatrix}
  2. ⓑ ( 11 4 ) \begin{pmatrix} 11 \\ 4 \end{pmatrix}

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Expanding a Binomial

Write in expanded form.

  1. ⓐ (x+y) 5 \left(x + y\right)^{5}
  2. ⓑ ( 3x−y ) 4 \left(3 x - y\right)^{4}
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13.6 Exercise 10

Write in expanded form.

  1. ⓐ (x−y) 5 \left(x - y\right)^{5}
  2. ⓑ (2x+5y) 3 \left(2 x + 5 y\right)^{3}
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Writing a Given Term of a Binomial Expansion

Find the tenth term of (x+2y) 16 \left(x + 2 y\right)^{16} without fully expanding the binomial.

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13.6 Exercise 12

Find the sixth term of (3x−y) 9 \left(3 x - y\right)^{9} without fully expanding the binomial.

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13.6 Exercise 13

What is a binomial coefficient, and how it is calculated?

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13.6 Exercise 15

What is the Binomial Theorem and what is its use?

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13.6 Exercise 17

Evaluate the binomial coefficient.

( 6 2 ) \begin{pmatrix} 6 \\ 2 \end{pmatrix}

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13.6 Exercise 19

Evaluate the binomial coefficient.

( 7 4 ) \begin{pmatrix} 7 \\ 4 \end{pmatrix}

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13.6 Exercise 21

Evaluate the binomial coefficient.

( 10 9 ) \begin{pmatrix} 10 \\ 9 \end{pmatrix}

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13.6 Exercise 23

Evaluate the binomial coefficient.

( 17 6 ) \begin{pmatrix} 17 \\ 6 \end{pmatrix}

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13.6 Exercise 25

Use the Binomial Theorem to expand each binomial.

(4a−b) 3 \left(4 a - b\right)^{3}

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13.6 Exercise 27

Use the Binomial Theorem to expand each binomial.

(3a+2b) 3 \left(3 a + 2 b\right)^{3}

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13.6 Exercise 29

Use the Binomial Theorem to expand each binomial.

(4x+2y) 5 \left(4 x + 2 y\right)^{5}

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13.6 Exercise 31

Use the Binomial Theorem to expand each binomial.

(4x−3y) 5 \left(4 x - 3 y\right)^{5}

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13.6 Exercise 33

Use the Binomial Theorem to expand each binomial.

( x −1 +2 y −1 ) 4 \left(x^{- 1} + 2 y^{- 1}\right)^{4}

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13.6 Exercise 35

Use the Binomial Theorem to write the first three terms of each binomial.

(a+b) 17 \left(a + b\right)^{17}

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13.6 Exercise 37

Use the Binomial Theorem to write the first three terms of each binomial.

(a−2b) 15 \left(a - 2 b\right)^{15}

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13.6 Exercise 39

Use the Binomial Theorem to write the first three terms of each binomial.

(3a+b) 20 \left(3 a + b\right)^{20}

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13.6 Exercise 41

Use the Binomial Theorem to write the first three terms of each binomial.

( x 3 − y ) 8 \left(x^{3} - \sqrt{y}\right)^{8}

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13.6 Exercise 43

Find the indicated term of each binomial without fully expanding the binomial.

The fourth term of (3x−2y) 5 \left(3 x - 2 y\right)^{5}

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13.6 Exercise 45

Find the indicated term of each binomial without fully expanding the binomial.

The eighth term of (7+5y) 14 \left(7 + 5 y\right)^{14}

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13.6 Exercise 47

Find the indicated term of each binomial without fully expanding the binomial.

The fifth term of (x−y) 7 \left(x - y\right)^{7}

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13.6 Exercise 49

Find the indicated term of each binomial without fully expanding the binomial.

The ninth term of (a−3 b 2 ) 11 \left(a - 3 b^{2}\right)^{11}

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13.6 Exercise 51

Find the indicated term of each binomial without fully expanding the binomial.

The eighth term of ( y 2 + 2 x ) 9 \left(\frac{y}{2} + \frac{2}{x}\right)^{9}

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13.6 Exercise 57

In the expansion of (5x+3y) n , \left(5 x + 3 y\right)^{n} , each term has the form ( n k ) a n–k b k \begin{pmatrix} n \\ k \end{pmatrix} a^{n – k} b^{k}, where k k successively takes on the value 0,1,2,...,n. 0 , 1 , 2 , ... , n . If ( n k )=( 7 2 ), \begin{pmatrix} n \\ k \end{pmatrix} = \begin{pmatrix} 7 \\ 2 \end{pmatrix} , what is the corresponding term?

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13.6 Exercise 59

Consider the expansion of (x+b) 40 . \left(x + b\right)^{40} . What is the exponent of b b in the kth k \text{th} term?

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13.6 Exercise 61

Which expression cannot be expanded using the Binomial Theorem? Explain.

  • ( x 2 −2x+1) \left(x^{2} - 2 x + 1\right)
  • ( a +4 a −5) 8 \left(\sqrt{a} + 4 \sqrt{a} - 5\right)^{8}
  • ( x 3 +2 y 2 −z) 5 \left(x^{3} + 2 y^{2} - z\right)^{5}
  • (3 x 2 − 2 y 3 ) 12 \left(3 x^{2} - \sqrt{2 y^{3}}\right)^{12}
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Adapted from College Algebra © 2021 Rice University. Licensed under CC BY 4.0. Sources: College Algebra 2e, Algebra and Trigonometry 2e, Precalculus 2e, College Algebra with Corequisite Support 2e. Imported at revision 4922e46.