I think it is -14. I inserted 4 as n. I don't know if that's how you do it.
I think the answer is (-6,30) unless I messed up somewhere
The formula is
YC x YD = AY x YB
fill in what we know:
18 x 6 = 9 x YB
108 = 9 x YB
YB = 108 / 9
YB = 12
(4 - -2) / (9 - 5) = 6/4 or 3/2
Let x = number of adult tickets sold
Let x-53 = number of student tickets sold
x + x -53 = 697
2x - 53 = 697.
Add 53 to both sides to get:
2x = 750
Divide both sides by 2 to get:
x = 375
375 adult tickets were sold.
