Graph between PV & P, Boyle's Law and its interpretation

My text book says: 



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> At higher constant temperature, the volume increase and value of product PV should increase due to increase of volume at same pressure, but PV remains constant at this new temperature & a straight line is obtained parallel to pressure axis in the fig 
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[![I could not get the idea if, this is a boyle's law then why pressure remains same instead of temperature?](https://i.stack.imgur.com/YNLo7.png)](https://i.stack.imgur.com/YNLo7.png)


I could not get the idea if, this is a Boyle's law then why pressure remains same instead of temperature?




That's the graph you get under **isothermal** conditions.


Recall the ideal gas equation of state:


$$PV = nRT$$


At isothermal conditions, temperature is constant (duh!), so as a result the $PV$ term is going to be constant as well. You may as well try changing the volume of your gas container, but pressure will just adjust itself to make sure $PV$ remains the same.


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