Key PointsBitcoin price failed to break the $6,800 resistance recently and declined against the US Dollar.There is a major bullish trend line in place with support at $6,400 on the 4-hours chart of the BTC/USD pair (data feed from Kraken).The pair must stay above the $6,400 and $6,380 support levels to remain in a positive zone.Bitcoin price is holding key supports against the US Dollar. BTC/USD could move higher once again as long as it is above the $6,400 support.Bitcoin Price AnalysisThis past week, bitcoin price made a nice upside move from the $6,300-6,310 zone against the US Dollar. The BTC/USD pair climbed higher and broke the $6,500 and $6,700 resistance levels. There was also a close above the $6,500 level and the 100 simple moving average (4-hours). However, the upside move was capped by the $8,000 resistance. The price declined and moved below the 50% Fib retracement level of the last wave from the $6,317 low to $6,800 high.Later, buyers appeared near the $6,450 level and the 100 SMA. Moreover, there was no test of the 76.4% Fib retracement level of the last wave from the $6,317 low to $6,800 high. On the downside, there is a strong support formed near the $6,400 and $6,380 levels.