Solve 5x^2 8x -4 - ScanMath

Question

Simplify the expression

40 x^{3} - 4

Evaluate

5 x^{2} \times 8 x - 4

Solution

More Steps

Evaluate

5 x^{2} \times 8 x

Multiply the terms

40 x^{2} \times x

Multiply the terms with the same base by adding their exponents

40 x^{2 + 1}

Add the numbers

40 x^{3}

40 x^{3} - 4

Show Solution

Factor the expression

4 (10 x^{3} - 1)

Evaluate

5 x^{2} \times 8 x - 4

Multiply

More Steps

Evaluate

5 x^{2} \times 8 x

Multiply the terms

40 x^{2} \times x

Multiply the terms with the same base by adding their exponents

40 x^{2 + 1}

Add the numbers

40 x^{3}

40 x^{3} - 4

Solution

4 (10 x^{3} - 1)

Show Solution

Find the roots

x = \frac{3 100}{10}

Alternative Form

x \approx 0.464159

Evaluate

5 x^{2} \times 8 x - 4

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

5 x^{2} \times 8 x - 4 = 0

Multiply

More Steps

Multiply the terms

5 x^{2} \times 8 x

Multiply the terms

40 x^{2} \times x

Multiply the terms with the same base by adding their exponents

40 x^{2 + 1}

Add the numbers

40 x^{3}

40 x^{3} - 4 = 0

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

40 x^{3} = 0 + 4

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

40 x^{3} = 4

Divide both sides

\frac{40 x ^{3}}{40} = \frac{4}{40}

Divide the numbers

x^{3} = \frac{4}{40}

Cancel out the common factor 4

x^{3} = \frac{1}{10}

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

3 x^{3} = 3 \frac{1}{10}

Calculate

x = 3 \frac{1}{10}

Solution

More Steps

Evaluate

3 \frac{1}{10}

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

\frac{3 1}{3 10}

Simplify the radical expression

\frac{1}{3 10}

Multiply by the Conjugate

\frac{3 1 0 ^{2}}{3 10 \times 3 1 0 ^{2}}

Simplify

\frac{3 100}{3 10 \times 3 1 0 ^{2}}

Multiply the numbers

More Steps

Evaluate

310 \times 3 1 0^{2}

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

3 10 \times 1 0^{2}

Calculate the product

3 1 0^{3}

Reduce the index of the radical and exponent with 3

10

\frac{3 100}{10}

x = \frac{3 100}{10}

Alternative Form

x \approx 0.464159

Show Solution