Solve 4r^25-2 - ScanMath

Question

Simplify the expression

20 r^{2} - 2

Evaluate

4 r^{2} \times 5 - 2

Solution

20 r^{2} - 2

Show Solution

2 (10 r^{2} - 1)

Evaluate

4 r^{2} \times 5 - 2

Multiply the terms

20 r^{2} - 2

Solution

2 (10 r^{2} - 1)

Show Solution

r_{1} = - \frac{10}{10}, r_{2} = \frac{10}{10}

Alternative Form

r_{1} \approx - 0.316228, r_{2} \approx 0.316228

Evaluate

4 r^{2} \times 5 - 2

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

4 r^{2} \times 5 - 2 = 0

Multiply the terms

20 r^{2} - 2 = 0

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

20 r^{2} = 0 + 2

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

20 r^{2} = 2

Divide both sides

\frac{20 r ^{2}}{20} = \frac{2}{20}

Divide the numbers

r^{2} = \frac{2}{20}

Cancel out the common factor 2

r^{2} = \frac{1}{10}

Take the root of both sides of the equation and remember to use both positive and negative roots

r = \pm \frac{1}{10}

Simplify the expression

More Steps

Evaluate

\frac{1}{10}

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

\frac{1}{10}

Simplify the radical expression

\frac{1}{10}

Multiply by the Conjugate

\frac{10}{10 \times 10}

When a square root of an expression is multiplied by itself,the result is that expression

\frac{10}{10}

r = \pm \frac{10}{10}

Separate the equation into 2 possible cases

r = \frac{10}{10} r = - \frac{10}{10}

Solution

r_{1} = - \frac{10}{10}, r_{2} = \frac{10}{10}

Alternative Form

r_{1} \approx - 0.316228, r_{2} \approx 0.316228

Show Solution