Answer:
k=20.
Explanation: First we find where f(x) has its local extrema: f'(x)=3x2−10x+3. The critical points are roots of the equation: 3x2−10x+3=0.
It must end in a 0 for the number to be divisible by 10. The other 5 can go in any order, so 5 factorial (5!) = 5*4*3*2*1
120 numbers
Depends of the size of the quadrilateral in relation to the circle, but otherwise, yes
