The school that lisa goes to is selling tickets to the annual talent show. on the first day of ticket sales the school sold 4 senior citizen tickets and 5 student tickets for a total of $102. the school took in $126 on the second day by selling 7 senior citizen tickets and 5 student tickets. what is the price each of senior citizen ticket and one student ticket?

Let:
x = cost of senior citizen ticket
y = cost of student ticket

4x + 5y = 102
7x + 5y = 126

4x + 5y = 102
4x = 102 - 5y
x = (102 - 5y)/4
x = 102/4 - 5y/4

7x + 5y = 126
7(102/4 - 5y/4) + 5y = 126
(714/4 - 35y/4) + 5y = 126
-35y/4 + 5y = 126 - 714/4

note:
-35y/4 = -8.75y
714/4 = 178.5

-8.75y + 5y = 126 - 178.5
-3.75y = -52.5
y = -52.5/-3.75
y = 14

x = 102/4 - 5y/4
x = 102/4 - 5(14)/4
x = 8

x = cost of senior citizen ticket = $8/ea
y = cost of student ticket = $14/ea

The answer would be -3.9> -4.5