Answer:
350 adult tickets were sold
Step-by-step explanation:
Let "a" represent the number of adult tickets sold. Then the number of student tickets is (a+69) and the total number of tickets sold is ...
a + (a+69) = 769
2a = 700 . . . . . . . . subtract 69
a = 350 . . . . . . . . . divide by 2
350 adult tickets were sold.
I believe is 70 multiply 1400 times 5% and it will give you 70
Y =3x+13---------#
-4x+3y=19-------*
subsititute value of y in equation *
-4x+3(3x+13)=19
-4x+9x+39=19
5x=-20
x=-20/5
x= -4