Solve 4x^2 5x-9 - ScanMath

Question

Simplify the expression

20 x^{3} - 9

Evaluate

4 x^{2} \times 5 x - 9

Solution

More Steps

Evaluate

4 x^{2} \times 5 x

Multiply the terms

20 x^{2} \times x

Multiply the terms with the same base by adding their exponents

20 x^{2 + 1}

Add the numbers

20 x^{3}

20 x^{3} - 9

Show Solution

x = \frac{3 450}{10}

Alternative Form

x \approx 0.766309

Evaluate

4 x^{2} \times 5 x - 9

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

4 x^{2} \times 5 x - 9 = 0

Multiply

More Steps

Multiply the terms

4 x^{2} \times 5 x

Multiply the terms

20 x^{2} \times x

Multiply the terms with the same base by adding their exponents

20 x^{2 + 1}

Add the numbers

20 x^{3}

20 x^{3} - 9 = 0

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

20 x^{3} = 0 + 9

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

20 x^{3} = 9

Divide both sides

\frac{20 x ^{3}}{20} = \frac{9}{20}

Divide the numbers

x^{3} = \frac{9}{20}

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

3 x^{3} = 3 \frac{9}{20}

Calculate

x = 3 \frac{9}{20}

Solution

More Steps

Evaluate

3 \frac{9}{20}

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

\frac{3 9}{3 20}

Multiply by the Conjugate

\frac{3 9 \times 3 2 0 ^{2}}{3 20 \times 3 2 0 ^{2}}

Simplify

\frac{3 9 \times 2 3 50}{3 20 \times 3 2 0 ^{2}}

Multiply the numbers

More Steps

Evaluate

39 \times 2350

Multiply the terms

3450 \times 2

Use the commutative property to reorder the terms

23450

\frac{2 3 450}{3 20 \times 3 2 0 ^{2}}

Multiply the numbers

More Steps

Evaluate

320 \times 3 2 0^{2}

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

3 20 \times 2 0^{2}

Calculate the product

3 2 0^{3}

Reduce the index of the radical and exponent with 3

20

\frac{2 3 450}{20}

Cancel out the common factor 2

\frac{3 450}{10}

x = \frac{3 450}{10}

Alternative Form

x \approx 0.766309

Show Solution