Answer:
69
Step-by-step explanation:
For this case we have that the commutative property establishes that the order of the factors does not alter the product. Example:

Then we have the following options illustrate the property:

It is necessary to emphasize that option b illustrates the associative property and in option c equality is not fulfilled
Answer:
Option A, D, E, F
6 is the highest common factor
Lagrange multipliers:







(if

)

(if

)

(if

)
In the first octant, we assume

, so we can ignore the caveats above. Now,

so that the only critical point in the region of interest is (1, 2, 2), for which we get a maximum value of

.
We also need to check the boundary of the region, i.e. the intersection of

with the three coordinate axes. But in each case, we would end up setting at least one of the variables to 0, which would force

, so the point we found is the only extremum.
B..............
c>=3 and n<0 and p<=(9-3 c)/n