Insert the y factor (2) into the equation. Once you have done that, you are left with 9(2)+6. If the y factor was not added into the equation, you wouldn't be able to solve the equation.
600 = 45x (x= minutes)
13.3333333=x
1*(2/3) = 80 minutes
80x= 13.333333*80
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Therefore the airplane flies 1066.66664 km in 80 minutes or 1 2/3 hours
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