Solve x^2 3x - 40 = 0

Question

Solve the equation

x = \frac{2 3 45}{3}

Alternative Form

x \approx 2.371262

Evaluate

x^{2} \times 3 x - 40 = 0

Multiply

More Steps

Evaluate

x^{2} \times 3 x

Multiply the terms with the same base by adding their exponents

x^{2 + 1} \times 3

Add the numbers

x^{3} \times 3

Use the commutative property to reorder the terms

3 x^{3}

3 x^{3} - 40 = 0

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

3 x^{3} = 0 + 40

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

3 x^{3} = 40

Divide both sides

\frac{3 x ^{3}}{3} = \frac{40}{3}

Divide the numbers

x^{3} = \frac{40}{3}

Take the 3 -th root on both sides of the equation

3 x^{3} = 3 \frac{40}{3}

Calculate

x = 3 \frac{40}{3}

Solution

More Steps

Evaluate

3 \frac{40}{3}

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

\frac{3 40}{3 3}

Simplify the radical expression

More Steps

Evaluate

340

Write the expression as a product where the root of one of the factors can be evaluated

3 8 \times 5

Write the number in exponential form with the base of 2

3 2^{3} \times 5

The root of a product is equal to the product of the roots of each factor

3 2^{3} \times 35

Reduce the index of the radical and exponent with 3

235

\frac{2 3 5}{3 3}

Multiply by the Conjugate

\frac{2 3 5 \times 3 3 ^{2}}{3 3 \times 3 3 ^{2}}

Simplify

\frac{2 3 5 \times 3 9}{3 3 \times 3 3 ^{2}}

Multiply the numbers

More Steps

Evaluate

35 \times 39

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

3 5 \times 9

Calculate the product

345

\frac{2 3 45}{3 3 \times 3 3 ^{2}}

Multiply the numbers

More Steps

Evaluate

33 \times 3 3^{2}

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

3 3 \times 3^{2}

Calculate the product

3 3^{3}

Reduce the index of the radical and exponent with 3

3

\frac{2 3 45}{3}

x = \frac{2 3 45}{3}

Alternative Form

x \approx 2.371262

Show Solution