Solve 7r^(3)-8r^(2) 42r-48

Question

Simplify the expression

- 329 r^{3} - 48

Show Solution

r = - \frac{2 3 6 \times 32 9 ^{2}}{329}

Alternative Form

r \approx - 0.526439

Evaluate

7 r^{3} - 8 r^{2} \times 42 r - 48

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

7 r^{3} - 8 r^{2} \times 42 r - 48 = 0

Multiply

More Steps

7 r^{3} - 336 r^{3} - 48 = 0

Subtract the terms

More Steps

- 329 r^{3} - 48 = 0

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

- 329 r^{3} = 0 + 48

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

- 329 r^{3} = 48

Change the signs on both sides of the equation

329 r^{3} = - 48

Divide both sides

\frac{329 r ^{3}}{329} = \frac{- 48}{329}

Divide the numbers

r^{3} = \frac{- 48}{329}

Use \frac{- a}{b} = \frac{a}{- b} = - \frac{a}{b} to rewrite the fraction

r^{3} = - \frac{48}{329}

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

3 r^{3} = 3 - \frac{48}{329}

Calculate

r = 3 - \frac{48}{329}

Solution

More Steps

r = - \frac{2 3 6 \times 32 9 ^{2}}{329}

Alternative Form

r \approx - 0.526439

Show Solution