x= small frames
y = large frames
6x+15y = 114
x+y = 13
solve for x
x=13-y
substitute into 6x+15y = 114
6(13-y) +15y = 114
distribute
78 -6y +15y = 114
combine like terms
78 +9y = 114
subtract 78 from each side
9y = 36
divide by 9
y =4
x = 13-y
x = 13-y
x=9
Answer: 9 small frames and 4 large frames