I am given the following two exercises:
For the first one (letter e), I proceeded as expected: wrote the 5 equations corresponding to the equality of the gradients (3 of those) and the other two constraints. I had to split into two cases: one for $\lambda = 0$ and another for $\lambda \neq 0$
For the exercise on letter f I am not sure what to do now. What should I do with the inequality $2z\leq 2x+y+4$? How should I proceed the exercise?