Iwas wondering if anyone could me solve this undergraduate level optimization problem.
prove that a concave function which is bounded from below in a polyhedron attains its minimum at one of the extremal points.

1- what do you think the product of a nonzero rational number and an irrational number is? is it rational or irrational? make use of variables, the closure property of integers, and possibly a proof by contradiction to prove your hypothesis.2- why do we have to specify that the rational number must be nonzero when we determine what the product of a nonzero rational number and an irrational number is? if the rational number were 0, would it give us the same result we found in the first question?

Which inequalities can be used to find the solution set of the following inequality? check all that apply. |2x – 5| (2x – 5) (2x + 5) –(2x – 5) –(2x + 5)

Aline is perpendicular to another line m2= (-1/m1), where m1 is the slope of the original line and m2 is the slope of the perpendicular line. which of the following equations represents the line that passes through the point (-2,1) and is perpendicular to the line below?