x= # of reserved seating
y= # of general admission
QUANTITY EQUATION:
x + y= 31,000
COST EQUATION:
14x + 5y= $200,000
STEP 1:
solve for either variable in quantity equation
x + y= 31,000
subtract both sides by y
x= 31000 -y
STEP 2:
substitute x=31000-y in cost equation
14x + 5y= $200,000
14(31000-y) +5y= 200000
434000 -14y + 5y= 200000
434000 - 9y= 200000
add 9y to both sides
434000= 200000 + 9y
subtract 200000 from both sides
234000= 9y
divide both sides by 9
26,000= y general admission
STEP 3:
substitute y answer in either equation
14x + 5y= $200,000
14x + 5(26000)= 200000
14x + 130000= 200000
14x= 70000
x= 5,000 reserved seats
CHECK:
14x + 5y= $200,000
14(5000) + 5(26000)= 200000
70000 + 130000= 200000
200000= 200000
ANSWER: There were 5,000 reserved seats and 26,000 general admission seats.
Hope this helps! :)