You can
put this solution on YOUR website!
Hi,
Let x represent number of general admission tickets
7x + 4(213-x) = 1146
7x + 852 - 4x = 1146
3x = 1146 - 852
3x = 294
x = 98, number of general admission tickets. 115 Student tickets 
CHECKING our answer***
$7*98 + $4* 115 = $686 + $460 = $1146
Wish You the Best in your Studies.