2 males 1 female guppies?

[IlhamSetiawan]

Is this possible?

[Guppysnail]

When the female is sexually mature having 2 males constantly harassing her will cause her a great deal of stress. They could potentially pester her to where she does not get enough to eat. They also could pester her while she is birthing so much she has trouble.
Not advisable but if that is the situation you are in provide extremely dense plants to include floating plant as well as structure from hardscape so she can find hiding places. 

[Cinnebuns]

Anything is possible but it may not be recommended. Like @Guppysnail mentioned, it may cause the female a high amount of stress. It may also cause fighting amoung the males. 2 males even without a female can cause fighting to the death. I will never say it's impossible but I also don't recommend it. 

[Ben P.]

Leave the female with the males for 2 days, you can by sure she'll be pregnant then.  Partition the tank so she's on one side and males on other.  She'll drop fry by herself, once the fry are 6 weeks old remove partition and you're good to go.  Enough bodies to keep the males aggression spread out

[lefty o]

its possible, but they will run her ragged. if you try it, make sure there are plenty of hiding places for her.