#6. if we make x the number of friends then 6x is the cost of their tickets. ($6 a piece) 
3 boxes of popcorn = 3($6) = $18
2 boxes of candy = 2($3.5) = $7 
total for snacks = $25 
6x + 25 <= 135 
answer C. 
#8. all angles add to 180 degree, solve for x. 
45x = 180 
x = 4