Solve 40x-12780x^5

Question

Factor the expression

20 x (2 - 639 x^{4})

Evaluate

40 x - 12780 x^{5}

Rewrite the expression

20 x \times 2 - 20 x \times 639 x^{4}

Solution

20 x (2 - 639 x^{4})

Show Solution

x_{1} = - \frac{4 2 \times 63 9 ^{3}}{639}, x_{2} = 0, x_{3} = \frac{4 2 \times 63 9 ^{3}}{639}

Alternative Form

x_{1} \approx - 0.236528, x_{2} = 0, x_{3} \approx 0.236528

Evaluate

40 x - 12780 x^{5}

To find the roots of the expression,set the expression equal to 0

40 x - 12780 x^{5} = 0

Factor the expression

20 x (2 - 639 x^{4}) = 0

Divide both sides

x (2 - 639 x^{4}) = 0

Separate the equation into 2 possible cases

x = 0 2 - 639 x^{4} = 0

Solve the equation

More Steps

Evaluate

2 - 639 x^{4} = 0

Move the constant to the right-hand side and change its sign

- 639 x^{4} = 0 - 2

Removing 0 doesn't change the value,so remove it from the expression

- 639 x^{4} = - 2

Change the signs on both sides of the equation

639 x^{4} = 2

Divide both sides

\frac{639 x ^{4}}{639} = \frac{2}{639}

Divide the numbers

x^{4} = \frac{2}{639}

Take the root of both sides of the equation and remember to use both positive and negative roots

x = \pm 4 \frac{2}{639}

Simplify the expression

More Steps

Evaluate

4 \frac{2}{639}

To take a root of a fraction,take the root of the numerator and denominator separately

\frac{4 2}{4 639}

Multiply by the Conjugate

\frac{4 2 \times 4 63 9 ^{3}}{4 639 \times 4 63 9 ^{3}}

The product of roots with the same index is equal to the root of the product

\frac{4 2 \times 63 9 ^{3}}{4 639 \times 4 63 9 ^{3}}

Multiply the numbers

\frac{4 2 \times 63 9 ^{3}}{639}

x = \pm \frac{4 2 \times 63 9 ^{3}}{639}

Separate the equation into 2 possible cases

x = \frac{4 2 \times 63 9 ^{3}}{639} x = - \frac{4 2 \times 63 9 ^{3}}{639}

x = 0 x = \frac{4 2 \times 63 9 ^{3}}{639} x = - \frac{4 2 \times 63 9 ^{3}}{639}

Solution

x_{1} = - \frac{4 2 \times 63 9 ^{3}}{639}, x_{2} = 0, x_{3} = \frac{4 2 \times 63 9 ^{3}}{639}

Alternative Form

x_{1} \approx - 0.236528, x_{2} = 0, x_{3} \approx 0.236528

Show Solution