Find Where Increasing/Decreasing f(x)=4x^3-5x^2-7x

$f (x) = 4 x^{3} - 5 x^{2} - 7 x$

Step 1

Graph the polynomial in order to determine the intervals over which it is increasing or decreasing.

Increasing on: $(- \infty, \frac{5 - \sqrt{109}}{12}), (\frac{5 + \sqrt{109}}{12}, \infty)$

Decreasing on: $(\frac{5 - \sqrt{109}}{12}, \frac{5 + \sqrt{109}}{12})$

Step 2