There are 4 people in the family, so they bought 4 tickets.
x = cost of 1 ticket
4x is the cost of 4 tickets.
You also have to add 12 for the popcorn.
4x + 12
They spent 40 in all, so it will be equal to 40.
4x + 12 = 40
Now you have to get the x on one side.
Subtract 12 first from both sides.
4x + 12 = 40
- 12 -12
4x = 28
Now you have to divide both sides by 4.
4x = 28
/4 /4
x = 7
Each ticket cost 7 dollars.
