Solve by Factoring 8x^4-10x^2+3=0

$8 x^{4} - 10 x^{2} + 3 = 0$

Step 1

Rewrite $x^{4}$ as ${(x^{2})}^{2}$ .

$8 {(x^{2})}^{2} - 10 x^{2} + 3 = 0$

Step 2

Let $u = x^{2}$ . Substitute $u$ for all occurrences of $x^{2}$ .

$8 u^{2} - 10 u + 3 = 0$

Step 3

Factor by grouping.

For a polynomial of the form $a x^{2} + b x + c$ , rewrite the middle term as a sum of two terms whose product is $a \cdot c = 8 \cdot 3 = 24$ and whose sum is $b = - 10$ .

Factor $- 10$ out of $- 10 u$ .

$8 u^{2} - 10 u + 3 = 0$

Rewrite $- 10$ as $- 4$ plus $- 6$

$8 u^{2} + (- 4 - 6) u + 3 = 0$

Apply the distributive property.

$8 u^{2} - 4 u - 6 u + 3 = 0$

Factor out the greatest common factor from each group.

Group the first two terms and the last two terms.

$(8 u^{2} - 4 u) - 6 u + 3 = 0$

Factor out the greatest common factor (GCF) from each group.

$4 u (2 u - 1) - 3 (2 u - 1) = 0$

Factor the polynomial by factoring out the greatest common factor, $2 u - 1$ .

$(2 u - 1) (4 u - 3) = 0$

Step 4

Replace all occurrences of $u$ with $x^{2}$ .

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

Step 5

If any individual factor on the left side of the equation is equal to $0$ , the entire expression will be equal to $0$ .

$2 x^{2} - 1 = 0$

$4 x^{2} - 3 = 0$

Step 6

Set $2 x^{2} - 1$ equal to $0$ and solve for $x$ .

Set $2 x^{2} - 1$ equal to $0$ .

$2 x^{2} - 1 = 0$

Solve $2 x^{2} - 1 = 0$ for $x$ .

Add $1$ to both sides of the equation.

$2 x^{2} = 1$

Divide each term in $2 x^{2} = 1$ by $2$ and simplify.

Divide each term in $2 x^{2} = 1$ by $2$ .

$\frac{2 x^{2}}{2} = \frac{1}{2}$

Simplify the left side.

Cancel the common factor of $2$ .

Cancel the common factor.

$\frac{2 x^{2}}{2} = \frac{1}{2}$

Divide $x^{2}$ by $1$ .

$x^{2} = \frac{1}{2}$

Take the specified root of both sides of the equation to eliminate the exponent on the left side.

$x = \pm \sqrt{\frac{1}{2}}$

Simplify $\pm \sqrt{\frac{1}{2}}$ .

Rewrite $\sqrt{\frac{1}{2}}$ as $\frac{\sqrt{1}}{\sqrt{2}}$ .

$x = \pm \frac{\sqrt{1}}{\sqrt{2}}$

Any root of $1$ is $1$ .

$x = \pm \frac{1}{\sqrt{2}}$

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

$x = \pm \frac{1}{\sqrt{2}} \cdot \frac{\sqrt{2}}{\sqrt{2}}$

Combine and simplify the denominator.

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

$x = \pm \frac{\sqrt{2}}{\sqrt{2} \sqrt{2}}$

Raise $\sqrt{2}$ to the power of $1$ .

$x = \pm \frac{\sqrt{2}}{{\sqrt{2}}^{1} \sqrt{2}}$

Raise $\sqrt{2}$ to the power of $1$ .

$x = \pm \frac{\sqrt{2}}{{\sqrt{2}}^{1} {\sqrt{2}}^{1}}$

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

$x = \pm \frac{\sqrt{2}}{{\sqrt{2}}^{1 + 1}}$

Add $1$ and $1$ .

$x = \pm \frac{\sqrt{2}}{{\sqrt{2}}^{2}}$

Rewrite ${\sqrt{2}}^{2}$ as $2$ .

Use $\sqrt[n]{a^{x}} = a^{\frac{x}{n}}$ to rewrite $\sqrt{2}$ as $2^{\frac{1}{2}}$ .

$x = \pm \frac{\sqrt{2}}{{(2^{\frac{1}{2}})}^{2}}$

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

$x = \pm \frac{\sqrt{2}}{2^{\frac{1}{2} \cdot 2}}$

Combine $\frac{1}{2}$ and $2$ .

$x = \pm \frac{\sqrt{2}}{2^{\frac{2}{2}}}$

Cancel the common factor of $2$ .

Cancel the common factor.

$x = \pm \frac{\sqrt{2}}{2^{\frac{2}{2}}}$

Rewrite the expression.

$x = \pm \frac{\sqrt{2}}{2^{1}}$

Evaluate the exponent.

$x = \pm \frac{\sqrt{2}}{2}$

The complete solution is the result of both the positive and negative portions of the solution.

First, use the positive value of the $\pm$ to find the first solution.

$x = \frac{\sqrt{2}}{2}$

Next, use the negative value of the $\pm$ to find the second solution.

$x = - \frac{\sqrt{2}}{2}$

The complete solution is the result of both the positive and negative portions of the solution.

$x = \frac{\sqrt{2}}{2}, - \frac{\sqrt{2}}{2}$

Step 7

Set $4 x^{2} - 3$ equal to $0$ and solve for $x$ .

Set $4 x^{2} - 3$ equal to $0$ .

$4 x^{2} - 3 = 0$

Solve $4 x^{2} - 3 = 0$ for $x$ .

Add $3$ to both sides of the equation.

$4 x^{2} = 3$

Divide each term in $4 x^{2} = 3$ by $4$ and simplify.

Divide each term in $4 x^{2} = 3$ by $4$ .

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

Simplify the left side.

Cancel the common factor of $4$ .

Cancel the common factor.

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

Divide $x^{2}$ by $1$ .

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

Take the specified root of both sides of the equation to eliminate the exponent on the left side.

$x = \pm \sqrt{\frac{3}{4}}$

Simplify $\pm \sqrt{\frac{3}{4}}$ .

Rewrite $\sqrt{\frac{3}{4}}$ as $\frac{\sqrt{3}}{\sqrt{4}}$ .

$x = \pm \frac{\sqrt{3}}{\sqrt{4}}$

Simplify the denominator.

Rewrite $4$ as $2^{2}$ .

$x = \pm \frac{\sqrt{3}}{\sqrt{2^{2}}}$

Pull terms out from under the radical, assuming positive real numbers.

$x = \pm \frac{\sqrt{3}}{2}$

The complete solution is the result of both the positive and negative portions of the solution.

First, use the positive value of the $\pm$ to find the first solution.

$x = \frac{\sqrt{3}}{2}$

Next, use the negative value of the $\pm$ to find the second solution.

$x = - \frac{\sqrt{3}}{2}$

The complete solution is the result of both the positive and negative portions of the solution.

$x = \frac{\sqrt{3}}{2}, - \frac{\sqrt{3}}{2}$

Step 8

The final solution is all the values that make $(2 x^{2} - 1) (4 x^{2} - 3) = 0$ true.

$x = \frac{\sqrt{2}}{2}, - \frac{\sqrt{2}}{2}, \frac{\sqrt{3}}{2}, - \frac{\sqrt{3}}{2}$

Step 9

The result can be shown in multiple forms.

Exact Form:

$x = \frac{\sqrt{2}}{2}, - \frac{\sqrt{2}}{2}, \frac{\sqrt{3}}{2}, - \frac{\sqrt{3}}{2}$

Decimal Form:

$x = 0.70710678 \dots, - 0.70710678 \dots, 0.86602540 \dots, - 0.86602540 \dots$

Solve by Factoring 8x^4-10x^2+3=0

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