So if you want to find the nth term so
1st term=1
2nd term=5
3rd term=25
we notice that 5^1=5 and 5^2=25 , but they are on the second ones so
the expression is
the nth term=5^(n-1)
so 1st term=5^(1-1)=5^0=1
2nd term=5^(2-1)=5^1=5
3rd term=5^(3-1)=5^2=25
and so on
the expression is 5^(n-1)
Your answer is 50 adult tickets and 70 children tickets hope this helps
*I'll be keeping the solutions in exact form*
So firstly, square root both sides. This will split the equation into two:

Next, add 1 on each side: 
Next, divide 3 on both sides, and your answers will be 
If it is 0.8x+c( i assume asin ur question it shows 08.x+c
Y=0.8x+c
Where x is number of gallon
Put x=1
y=5.8
X
x=2 then y=6.6
Every timeit is incresedby 0.8