9000070406
Level:
A
Given function \(f(x)= x^{3} + 6x^{2} - 15x + 7\), find
the intervals where \(f\)
is an increasing function.
\(\left (-\infty ,-5\right )\)
\(\left (-\infty ,-3\right )\)
\(\left (-1,\infty \right )\)
\(\left (-3,\infty \right )\)