Solve x^2 7x -18 - ScanMath

Question

Simplify the expression

7 x^{3} - 18

Evaluate

x^{2} \times 7 x - 18

Solution

More Steps

Evaluate

x^{2} \times 7 x

Multiply the terms with the same base by adding their exponents

x^{2 + 1} \times 7

Add the numbers

x^{3} \times 7

Use the commutative property to reorder the terms

7 x^{3}

7 x^{3} - 18

Show Solution

x = \frac{3 882}{7}

Alternative Form

x \approx 1.370013

Evaluate

x^{2} \times 7 x - 18

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

x^{2} \times 7 x - 18 = 0

Multiply

More Steps

Multiply the terms

x^{2} \times 7 x

Multiply the terms with the same base by adding their exponents

x^{2 + 1} \times 7

Add the numbers

x^{3} \times 7

Use the commutative property to reorder the terms

7 x^{3}

7 x^{3} - 18 = 0

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

7 x^{3} = 0 + 18

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

7 x^{3} = 18

Divide both sides

\frac{7 x ^{3}}{7} = \frac{18}{7}

Divide the numbers

x^{3} = \frac{18}{7}

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

3 x^{3} = 3 \frac{18}{7}

Calculate

x = 3 \frac{18}{7}

Solution

More Steps

Evaluate

3 \frac{18}{7}

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

\frac{3 18}{3 7}

Multiply by the Conjugate

\frac{3 18 \times 3 7 ^{2}}{3 7 \times 3 7 ^{2}}

Simplify

\frac{3 18 \times 3 49}{3 7 \times 3 7 ^{2}}

Multiply the numbers

More Steps

Evaluate

318 \times 349

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

3 18 \times 49

Calculate the product

3882

\frac{3 882}{3 7 \times 3 7 ^{2}}

Multiply the numbers

More Steps

Evaluate

37 \times 3 7^{2}

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

3 7 \times 7^{2}

Calculate the product

3 7^{3}

Reduce the index of the radical and exponent with 3

7

\frac{3 882}{7}

x = \frac{3 882}{7}

Alternative Form

x \approx 1.370013

Show Solution