Minta tolong ya kakak2 yg jago matematika, nomer 2 beserta caranya

please find the answer

Nilai Maksimum /minimum pd titik pojok

a. f(x,y) = 3x + 5y
f(1,1)  = 3(1) + 5(1)= 8
f(6,3) = 3(6) +5(3) = 26
f(2,7) = 3(2) + 5(7) = 41
f(5,10) = 3(5)+ 5(10)= 65
minimum = 8
maksimum = 65

b. f(x,y) = 6x + y
f(1,3) = 6(1) + 1(3) = 9
f(1,5) = 6(1) + 1(5) = 11
f(6,8  = 6(6) + 1(8) = 44
f(9,1) = 6(9) + 1(1) = 55
minimum = 9
maksimum = 55