Algebra Examples

${(2 x - 5)}^{3}$

Step 1

Use the binomial expansion theorem to find each term. The binomial theorem states ${(a + b)}^{n} = \sum_{k = 0}^{n} n C k \cdot (a^{n - k} b^{k})$ .

$\sum_{k = 0}^{3} \frac{3!}{(3 - k)! k!} \cdot {(2 x)}^{3 - k} \cdot {(- 5)}^{k}$

Step 2

Expand the summation.

$\frac{3!}{(3 - 0)! 0!} \cdot {(2 x)}^{3 - 0} \cdot {(- 5)}^{0} + \frac{3!}{(3 - 1)! 1!} \cdot {(2 x)}^{3 - 1} \cdot {(- 5)}^{1} + \frac{3!}{(3 - 2)! 2!} \cdot {(2 x)}^{3 - 2} \cdot {(- 5)}^{2} + \frac{3!}{(3 - 3)! 3!} \cdot {(2 x)}^{3 - 3} \cdot {(- 5)}^{3}$

Step 3

Simplify the exponents for each term of the expansion.

$1 \cdot {(2 x)}^{3} \cdot {(- 5)}^{0} + 3 \cdot {(2 x)}^{2} \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4

Simplify each term.

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Step 4.1

Multiply ${(2 x)}^{3}$ by $1$ .

${(2 x)}^{3} \cdot {(- 5)}^{0} + 3 \cdot {(2 x)}^{2} \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.2

Apply the product rule to $2 x$ .

$2^{3} x^{3} \cdot {(- 5)}^{0} + 3 \cdot {(2 x)}^{2} \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.3

Raise $2$ to the power of $3$ .

$8 x^{3} \cdot {(- 5)}^{0} + 3 \cdot {(2 x)}^{2} \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.4

Anything raised to $0$ is $1$ .

$8 x^{3} \cdot 1 + 3 \cdot {(2 x)}^{2} \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.5

Multiply $8$ by $1$ .

$8 x^{3} + 3 \cdot {(2 x)}^{2} \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.6

Apply the product rule to $2 x$ .

$8 x^{3} + 3 \cdot (2^{2} x^{2}) \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.7

Raise $2$ to the power of $2$ .

$8 x^{3} + 3 \cdot (4 x^{2}) \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.8

Multiply $4$ by $3$ .

$8 x^{3} + 12 x^{2} \cdot {(- 5)}^{1} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.9

Evaluate the exponent.

$8 x^{3} + 12 x^{2} \cdot - 5 + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.10

Multiply $- 5$ by $12$ .

$8 x^{3} - 60 x^{2} + 3 \cdot {(2 x)}^{1} \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.11

Simplify.

$8 x^{3} - 60 x^{2} + 3 \cdot (2 x) \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.12

Multiply $2$ by $3$ .

$8 x^{3} - 60 x^{2} + 6 x \cdot {(- 5)}^{2} + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.13

Raise $- 5$ to the power of $2$ .

$8 x^{3} - 60 x^{2} + 6 x \cdot 25 + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.14

Multiply $25$ by $6$ .

$8 x^{3} - 60 x^{2} + 150 x + 1 \cdot {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.15

Multiply ${(2 x)}^{0}$ by $1$ .

$8 x^{3} - 60 x^{2} + 150 x + {(2 x)}^{0} \cdot {(- 5)}^{3}$

Step 4.16

Apply the product rule to $2 x$ .

$8 x^{3} - 60 x^{2} + 150 x + 2^{0} x^{0} \cdot {(- 5)}^{3}$

Step 4.17

Anything raised to $0$ is $1$ .

$8 x^{3} - 60 x^{2} + 150 x + 1 x^{0} \cdot {(- 5)}^{3}$

Step 4.18

Multiply $x^{0}$ by $1$ .

$8 x^{3} - 60 x^{2} + 150 x + x^{0} \cdot {(- 5)}^{3}$

Step 4.19

Anything raised to $0$ is $1$ .

$8 x^{3} - 60 x^{2} + 150 x + 1 \cdot {(- 5)}^{3}$

Step 4.20

Multiply ${(- 5)}^{3}$ by $1$ .

$8 x^{3} - 60 x^{2} + 150 x + {(- 5)}^{3}$

Step 4.21

Raise $- 5$ to the power of $3$ .

$8 x^{3} - 60 x^{2} + 150 x - 125$