Given 7x + 11y = n, what is the highest number n can be to produce an answer of no solution. (x, y) must be positive.

Since x and y must be positive, 7x and 11y are positive either. That means 7x + 11y > 0. Then we would obtain N > 0 because 7x + 11y = N. That also means N must be positive. So if we set N to be zero or negative, there would be no solution. Thus, to produce an answer of No solution, the highest number N could be is 0. 

Since x and y must be positive, 7x and 11y are positive either. That means 7x + 11y > 0. Then we would obtain N > 0 because 7x + 11y = N. That also means N must be positive. So if we set N to be zero or negative, there would be no solution. Thus, to produce an answer of No solution, the highest number N could be is 0.