Placing CTA in left or right side?

Most websites will have the main form ( book a hotel, a flight etc. ) placed either on the center of the page or on the left side. I cannot recall any that has it placed on the right side.

The website I am redesigning has this form on the right side and while I find it logical to have it sit on the left side, I am looking for some information regarding this so I can argument my decision rather than base it on intuition.

The other issue is that present users might be adjusted to how the page is currently made but we are looking to also find new users ...

Ex: