I use 0ne 150 watt bulb as light fixture says per week can not find out why they go so soon

You can't touch them, or clean.
Oil from your fingers decrease the life of the bulb.

The halogen bulb is basically an tungsten filament bulb and is extremely sensitive to overvoltage. The life is calculated by an exponential function based voltage applied. Please check the voltage rating of the bulbs you are using and then check to ensure you are supplying no more than the nameplate voltage shown on the lamp you are using. At a maximum the allowed overvoltage is about 5 volts which will reduce the life of the lamp by about 50%.
Hope this helps,
Newton1Law