Putting energy equals same energy gained

I am not sure I understand the question. The conservation of energy is a basic law of classical physics. It works like this.

When you blow up a balloon, you expend energy (which comes from the chemical energy of carbohydrates in the food you ate that your muscles convert into kinetic energy) that you put into the balloon by doing work. That energy goes into a couple of different places.

- potential energy of a blown up balloon (which you can easily recover if you let the balloon go and watch it move around like crazy).
- Noise (yes, the noise you make blowing up the balloon is energy and is wasted). This includes the stretching rubber noises and the rushing air noises.
- Heat (yep... you heat up the balloon as you blow into it).

So no, the potential energy will not be exactly equal to the energy you expend. You will lose some of that energy to noise and heat right away.

My profession is currently software engineer, but many years ago I taught Physics.