Question

The maximum is at (8, 2).

Answer 1

@phi

Answer 2

you have to plot all of those relations, and find the vertices. At each vertex (corner)
use f(x,y) to evaluate that point. Pick the point that gives the biggest f(x,y)

Answer 3

hm can u do it step by step for me? :/

Answer 4

is there anyway i can do it on my calculator?

Answer 5

can you download geogebra ?
http://www.geogebra.org/cms/en/

Here is what I came up with

Answer 6

thankyouuu!!!! <3

Answer 7

at each point A, B and C
you use the (x,y) value of the point and compute f(x,y)= 9x + 5y
and pick the point that has the biggest f(x,y)