Question 684094
x =  adult
y = students
...
6x+4.5y=1065
x+y=210 ==> rearrange as x = 210-y
...
Substitution
6(210-y) + 4.5y = 1065
1260 - 6y + 4.5y = 1065
1260 - 1.5y = 1065
-1.5y = 1065-1260
-1.5y = -195
y = 130 student's tickets
...
x + 130 = 210
x = 210 - 130 = 80 adult tickets
.....................
Have more questions? 
Email: HomeworkHelpers@readingboosters.com
Delighted to help.
-Reading Boosters
Website: www.MyHomeworkAnswers.com 
Wanting for others what we want for ourselves.