Critical Points of f(x,y) = xy(1 - 5x - 8y): list by type

[italia]

I need to find the 4 critical points:

The function f(x,y)=xy(1-5x-8y) has 4 critical points. List them and select the type of critical point.

Points should be entered as ordered pairs and listed in increasing lexicographic order. By that we mean that (x,y) comes before (z,w) if x < z or if x = z and y < w.

First point_________of type ?
Second point_________of type ?
Third point_________of type ?
Fourth point_________of type ?

 

[Deleted member 4993]

I need to find the 4 critical points:

The function f(x,y)=xy(1-5x-8y) has 4 critical points. List them and select the type of critical point.

Points should be entered as ordered pairs and listed in increasing lexicographic order. By that we mean that (x,y) comes before (z,w) if x < z or if x = z and y < w.

First point_________of type ?
Second point_________of type ?
Third point_________of type ?
Fourth point_________of type ?

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