First of all you need to understand what actually the boiling point of a liqiud is. The Boiling point of a liquid is the temperature at which the vapour pressure of the liquid equals the external pressure.
Also the vapour pressure of a liquid is a function of the temperature. As the temperature increases, the vapour pressure increases.
Now if we increase the external pressure, a higher temperature would be required so that the vapour pressure equals the external pressure and hence the boiling point of the liquid increases.
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Dear student 
Boiling point is a temperature at which vapour pressure of liquid is equal to the atmospheric pressure around it.
If we apply vaccum, that means it sucks all the gas molecules in the container as well as it tries to pluck out the surface molecules of the liquid which increases interparticular distance and reduces inter particular forces so the bp decreases. Now the opposite way, if we increase pressure we are pushing the molecules closer which decreases inter particular distance where attractions will increase so bp increases with pressure.
Hope this helps