i have 2 questions that really bothering me all the time. First is, how do I make straight loop cut based on the image below in red line. 2 lines which is not straight and not in same angle each other. The second question is i want to move slide along the edge, just want to make my orange line straight align with my blue dot vertex. Again, 2 lines which is not straight and not in same angle for each other. Actually I can do it easily in max but I want to improve my blender skill so I can leave this expensive software. Humble thank you for your help.
As I understand from your description, you use loop cut tool from toolbar:
So then you press to make a cut, not release mouse button, instead move cursor to the sides, and you will see that you are able to slide loop cut to the sides. Release button only then you like the position of the cut.
If you press E while holding the mouse button, you will see that the loop cut is parallel to one side. If that side is wrong, press F to flip the side.
Also, you can use knife tool which give more freedom in making cuts.
If you press A after adding the first point, you will be able to make perfect horizontal or vertical cuts.
Information about available keys you can see in the toolbar: