this question concernc the function

f(x)=2x^3+15x^2+24x-21.
Using the Second Derivative Test ,cassify the right-hand stationary point .
please need your help
thanks for reading

f' = 6 x^2 + 30 x + 24 =6(x^2+5x+4)

=6(x+4)(x+1)
zero when x = -4 and - 1, so -1 is right point
f" = 12 x + 30
when x = -1
f" = -12 + 30 which is positive.
so this is a minimum, the function climbs on both sides of x = -1