F ( x ) = ( x - 2 ) ^3
x = ( y - 2 ) ^ 3
y = + 2
f ( x ) = ( x - 2)^3 is f^-1 ( x ) = + 2
i have this what do i do for this
Find f ( f^-1( x ) )

If it 8 inch candle burns at 7/10 inch per hour and a 6 inch candle burns at 1/5 inch per hour after how many hours would both candles be the same height