fx=3x? +6x-9=3(x? +2x-3)=3(x+3)(x- 1)=0
x 1=-3,x2= 1
fy=-3y? +6y=-3y(y-2)=0
y 1=0,y2=2
The stagnation point is (-3,0) (10) (-3,2) (12).
fxx=6x+6=A,fxy=0=B,fyy=-6y+6=C
1.(-3,0)
AC-B? & lt Zero Infinite Value
2.(-3,2)AC-B? & gt0 has extreme value.
3.( 1,0)
AC-B? = 72>0 has extreme value.
4.( 1,2)
AC-B? =-72 & lt; Zero infinite value
therefore
Choose advertising
2. BC
3. alternating current
4. Bachelor of Science
5. BC
6.B
7.B
8.B
9.B
10.B