Posted by Pd on .
f(x)=x^3+3x^2+9x5
asked to find the stationary points this was my working and i don't know if it is correct
f dash of x = 3x^2+3(2x)+9
3x^2+6x+9
at local max and min f(x) should =0
3x^2+6x+9=0
3x^26x+9
x^22x+3=0
stationary points would be at (x+3) (x3)
but am i right... if not a nudge in the right direction would be a great help

math 
bobpursley,
factor x^22x+3
(x3)(x+1)=0
x=3 x=1