Question 1007213
Call the number of general and VIP tickets, g and v.  Then we have
g + v = 29  and
60g + 90v = 2100
Now multiply the top equation by 60 and subtract from the second one and get
60g + 90v = 2100
-(60g + 60v = 1740)
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30v = 360
v = 12 VIP tickets
g = 17 general tickets