Solve by Factoring x^(3/4)=8

$x^{\frac{3}{4}} = 8$

Step 1

Subtract $8$ from both sides of the equation.

$x^{\frac{3}{4}} - 8 = 0$

Step 2

Rewrite $x^{\frac{3}{4}}$ as ${(x^{\frac{1}{4}})}^{3}$ .

${(x^{\frac{1}{4}})}^{3} - 8 = 0$

Step 3

Rewrite $8$ as $2^{3}$ .

${(x^{\frac{1}{4}})}^{3} - 2^{3} = 0$

Step 4

Since both terms are perfect cubes, factor using the difference of cubes formula, $a^{3} - b^{3} = (a - b) (a^{2} + a b + b^{2})$ where $a = x^{\frac{1}{4}}$ and $b = 2$ .

$(x^{\frac{1}{4}} - 2) ({(x^{\frac{1}{4}})}^{2} + x^{\frac{1}{4}} \cdot 2 + 2^{2}) = 0$

Step 5

Simplify.

Multiply the exponents in ${(x^{\frac{1}{4}})}^{2}$ .

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$(x^{\frac{1}{4}} - 2) (x^{\frac{1}{4} \cdot 2} + x^{\frac{1}{4}} \cdot 2 + 2^{2}) = 0$

Cancel the common factor of $2$ .

Factor $2$ out of $4$ .

$(x^{\frac{1}{4}} - 2) (x^{\frac{1}{2 (2)} \cdot 2} + x^{\frac{1}{4}} \cdot 2 + 2^{2}) = 0$

Cancel the common factor.

$(x^{\frac{1}{4}} - 2) (x^{\frac{1}{2 \cdot 2} \cdot 2} + x^{\frac{1}{4}} \cdot 2 + 2^{2}) = 0$

Rewrite the expression.

$(x^{\frac{1}{4}} - 2) (x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 2 + 2^{2}) = 0$

Move $2$ to the left of $x^{\frac{1}{4}}$ .

$(x^{\frac{1}{4}} - 2) (x^{\frac{1}{2}} + 2 x^{\frac{1}{4}} + 2^{2}) = 0$

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

$(x^{\frac{1}{4}} - 2) (x^{\frac{1}{2}} + 2 x^{\frac{1}{4}} + 4) = 0$

Reorder terms.

$(x^{\frac{1}{4}} - 2) (2 x^{\frac{1}{4}} + x^{\frac{1}{2}} + 4) = 0$

Step 6

Simplify $(x^{\frac{1}{4}} - 2) (2 x^{\frac{1}{4}} + x^{\frac{1}{2}} + 4)$ .

Expand $(x^{\frac{1}{4}} - 2) (2 x^{\frac{1}{4}} + x^{\frac{1}{2}} + 4)$ by multiplying each term in the first expression by each term in the second expression.

$x^{\frac{1}{4}} (2 x^{\frac{1}{4}}) + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Simplify terms.

Simplify each term.

Rewrite using the commutative property of multiplication.

$2 x^{\frac{1}{4}} x^{\frac{1}{4}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Multiply $x^{\frac{1}{4}}$ by $x^{\frac{1}{4}}$ by adding the exponents.

Move $x^{\frac{1}{4}}$ .

$2 (x^{\frac{1}{4}} x^{\frac{1}{4}}) + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$2 x^{\frac{1}{4} + \frac{1}{4}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Combine the numerators over the common denominator.

$2 x^{\frac{1 + 1}{4}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Add $1$ and $1$ .

$2 x^{\frac{2}{4}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Cancel the common factor of $2$ and $4$ .

Factor $2$ out of $2$ .

$2 x^{\frac{2 (1)}{4}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Cancel the common factors.

Factor $2$ out of $4$ .

$2 x^{\frac{2 \cdot 1}{2 \cdot 2}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Cancel the common factor.

$2 x^{\frac{2 \cdot 1}{2 \cdot 2}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Rewrite the expression.

$2 x^{\frac{1}{2}} + x^{\frac{1}{4}} x^{\frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Multiply $x^{\frac{1}{4}}$ by $x^{\frac{1}{2}}$ by adding the exponents.

Use the power rule $a^{m} a^{n} = a^{m + n}$ to combine exponents.

$2 x^{\frac{1}{2}} + x^{\frac{1}{4} + \frac{1}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

To write $\frac{1}{2}$ as a fraction with a common denominator, multiply by $\frac{2}{2}$ .

$2 x^{\frac{1}{2}} + x^{\frac{1}{4} + \frac{1}{2} \cdot \frac{2}{2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Write each expression with a common denominator of $4$ , by multiplying each by an appropriate factor of $1$ .

Multiply $\frac{1}{2}$ by $\frac{2}{2}$ .

$2 x^{\frac{1}{2}} + x^{\frac{1}{4} + \frac{2}{2 \cdot 2}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Multiply $2$ by $2$ .

$2 x^{\frac{1}{2}} + x^{\frac{1}{4} + \frac{2}{4}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Combine the numerators over the common denominator.

$2 x^{\frac{1}{2}} + x^{\frac{1 + 2}{4}} + x^{\frac{1}{4}} \cdot 4 - 2 (2 x^{\frac{1}{4}}) - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Add $1$ and $2$ .

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

Move $4$ to the left of $x^{\frac{1}{4}}$ .

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

Multiply $2$ by $- 2$ .

$2 x^{\frac{1}{2}} + x^{\frac{3}{4}} + 4 x^{\frac{1}{4}} - 4 x^{\frac{1}{4}} - 2 x^{\frac{1}{2}} - 2 \cdot 4 = 0$

Multiply $- 2$ by $4$ .

$2 x^{\frac{1}{2}} + x^{\frac{3}{4}} + 4 x^{\frac{1}{4}} - 4 x^{\frac{1}{4}} - 2 x^{\frac{1}{2}} - 8 = 0$

Combine the opposite terms in $2 x^{\frac{1}{2}} + x^{\frac{3}{4}} + 4 x^{\frac{1}{4}} - 4 x^{\frac{1}{4}} - 2 x^{\frac{1}{2}} - 8$ .

Subtract $4 x^{\frac{1}{4}}$ from $4 x^{\frac{1}{4}}$ .

$2 x^{\frac{1}{2}} + x^{\frac{3}{4}} + 0 - 2 x^{\frac{1}{2}} - 8 = 0$

Add $2 x^{\frac{1}{2}} + x^{\frac{3}{4}}$ and $0$ .

$2 x^{\frac{1}{2}} + x^{\frac{3}{4}} - 2 x^{\frac{1}{2}} - 8 = 0$

Subtract $2 x^{\frac{1}{2}}$ from $2 x^{\frac{1}{2}}$ .

$x^{\frac{3}{4}} + 0 - 8 = 0$

Add $x^{\frac{3}{4}}$ and $0$ .

$x^{\frac{3}{4}} - 8 = 0$

Step 7

Add $8$ to both sides of the equation.

$x^{\frac{3}{4}} = 8$

Step 8

Raise each side of the equation to the power of $\frac{4}{3}$ to eliminate the fractional exponent on the left side.

${(x^{\frac{3}{4}})}^{\frac{4}{3}} = 8^{\frac{4}{3}}$

Step 9

Simplify the exponent.

Simplify the left side.

Simplify ${(x^{\frac{3}{4}})}^{\frac{4}{3}}$ .

Multiply the exponents in ${(x^{\frac{3}{4}})}^{\frac{4}{3}}$ .

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$x^{\frac{3}{4} \cdot \frac{4}{3}} = 8^{\frac{4}{3}}$

Cancel the common factor of $3$ .

Cancel the common factor.

$x^{\frac{3}{4} \cdot \frac{4}{3}} = 8^{\frac{4}{3}}$

Rewrite the expression.

$x^{\frac{1}{4} \cdot 4} = 8^{\frac{4}{3}}$

Cancel the common factor of $4$ .

Cancel the common factor.

$x^{\frac{1}{4} \cdot 4} = 8^{\frac{4}{3}}$

Rewrite the expression.

$x^{1} = 8^{\frac{4}{3}}$

Simplify.

$x = 8^{\frac{4}{3}}$

Simplify the right side.

Simplify $8^{\frac{4}{3}}$ .

Simplify the expression.

Rewrite $8$ as $2^{3}$ .

$x = {(2^{3})}^{\frac{4}{3}}$

Apply the power rule and multiply exponents, ${(a^{m})}^{n} = a^{m n}$ .

$x = 2^{3 (\frac{4}{3})}$

Cancel the common factor of $3$ .

Cancel the common factor.

$x = 2^{3 (\frac{4}{3})}$

Rewrite the expression.

$x = 2^{4}$

Raise $2$ to the power of $4$ .

$x = 16$

Solve by Factoring x^(3/4)=8

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