Find the critical points of the given function and then determine whether they are local maxima, local minima, or saddle points. f(x, y) = x2 + y2 + 2xy

The diagonals of a quadrilaretral intersect at (-1,4). one of the sides of the quadrilateral is bounded by (2,7) and (-3,5) determine the coordinates of the other side in order for the quadrilaretral to be a square.

8. kelly wants to buy a magazine that is $25. later the magazine was marked up an additional 20%. what is the new price?

The anwser cause i do not understand just plez