Solve 3x^2 5x-7 - ScanMath

Question

Simplify the expression

15 x^{3} - 7

Evaluate

3 x^{2} \times 5 x - 7

Solution

More Steps

Evaluate

3 x^{2} \times 5 x

Multiply the terms

15 x^{2} \times x

Multiply the terms with the same base by adding their exponents

15 x^{2 + 1}

Add the numbers

15 x^{3}

15 x^{3} - 7

Show Solution

x = \frac{3 1575}{15}

Alternative Form

x \approx 0.775656

Evaluate

3 x^{2} \times 5 x - 7

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

3 x^{2} \times 5 x - 7 = 0

Multiply

More Steps

Multiply the terms

3 x^{2} \times 5 x

Multiply the terms

15 x^{2} \times x

Multiply the terms with the same base by adding their exponents

15 x^{2 + 1}

Add the numbers

15 x^{3}

15 x^{3} - 7 = 0

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

15 x^{3} = 0 + 7

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

15 x^{3} = 7

Divide both sides

\frac{15 x ^{3}}{15} = \frac{7}{15}

Divide the numbers

x^{3} = \frac{7}{15}

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

3 x^{3} = 3 \frac{7}{15}

Calculate

x = 3 \frac{7}{15}

Solution

More Steps

Evaluate

3 \frac{7}{15}

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

\frac{3 7}{3 15}

Multiply by the Conjugate

\frac{3 7 \times 3 1 5 ^{2}}{3 15 \times 3 1 5 ^{2}}

Simplify

\frac{3 7 \times 3 225}{3 15 \times 3 1 5 ^{2}}

Multiply the numbers

More Steps

Evaluate

37 \times 3225

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

3 7 \times 225

Calculate the product

31575

\frac{3 1575}{3 15 \times 3 1 5 ^{2}}

Multiply the numbers

More Steps

Evaluate

315 \times 3 1 5^{2}

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

3 15 \times 1 5^{2}

Calculate the product

3 1 5^{3}

Reduce the index of the radical and exponent with 3

15

\frac{3 1575}{15}

x = \frac{3 1575}{15}

Alternative Form

x \approx 0.775656

Show Solution