The answer obviously depends on what the boundaries of the feasibility region are.
maximum value of 6y+10y
60
It is an equation and the value of x works out as 88
-3
7.7
It would depend on the feasible region.
maximum value of 6y+10y
42
14
(6x)(5y)
78
Since there is no feasible region defined, there is no answer possible.
It is 18.
The answer depends on the feasible region and there is no information on which to determine that.
2x+2y
If we knew the values of 'x' and 'y', and the boundaries of the feasible region, we could answer that question quickly and easily.
It is 18.