Solve 3x^2 28x -378

Question

Simplify the expression

Solution

84 x^{3} - 378

Evaluate

3 x^{2} \times 28 x - 378

Solution

More Steps

Evaluate

3 x^{2} \times 28 x

Multiply the terms

84 x^{2} \times x

Multiply the terms with the same base by adding their exponents

84 x^{2 + 1}

Add the numbers

84 x^{3}

84 x^{3} - 378

Show Solution

Factor the expression

Factor

42 (2 x^{3} - 9)

Evaluate

3 x^{2} \times 28 x - 378

Multiply

More Steps

Evaluate

3 x^{2} \times 28 x

Multiply the terms

84 x^{2} \times x

Multiply the terms with the same base by adding their exponents

84 x^{2 + 1}

Add the numbers

84 x^{3}

84 x^{3} - 378

Solution

42 (2 x^{3} - 9)

Show Solution

Find the roots

Find the roots of the algebra expression

x = \frac{3 36}{2}

Alternative Form

x \approx 1.650964

Evaluate

3 x^{2} \times 28 x - 378

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

3 x^{2} \times 28 x - 378 = 0

Multiply

More Steps

Multiply the terms

3 x^{2} \times 28 x

Multiply the terms

84 x^{2} \times x

Multiply the terms with the same base by adding their exponents

84 x^{2 + 1}

Add the numbers

84 x^{3}

84 x^{3} - 378 = 0

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

84 x^{3} = 0 + 378

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

84 x^{3} = 378

Divide both sides

\frac{84 x ^{3}}{84} = \frac{378}{84}

Divide the numbers

x^{3} = \frac{378}{84}

Cancel out the common factor 42

x^{3} = \frac{9}{2}

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

3 x^{3} = 3 \frac{9}{2}

Calculate

x = 3 \frac{9}{2}

Solution

More Steps

Evaluate

3 \frac{9}{2}

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

\frac{3 9}{3 2}

Multiply by the Conjugate

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

Simplify

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

Multiply the numbers

More Steps

Evaluate

39 \times 34

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

3 9 \times 4

Calculate the product

336

\frac{3 36}{3 2 \times 3 2 ^{2}}

Multiply the numbers

More Steps

Evaluate

32 \times 3 2^{2}

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

3 2 \times 2^{2}

Calculate the product

3 2^{3}

Reduce the index of the radical and exponent with 3

2

\frac{3 36}{2}

x = \frac{3 36}{2}

Alternative Form

x \approx 1.650964

Show Solution

3x^2 28x 378

Simplify the expression

Factor the expression

Find the roots