The Equation Editor is programmed so that an equation object (the box you type into) is alone in a paragraph, it defaults to centered. If you add any character before or after the equation object, the editor makes it "in line with text".
This suggests that you can align all your equations where you want them by typing one or more spaces or a tab at the left margin before pressing Alt+= to start the equation:

The drawback (depending on your preferences) is that an in-line equation always reduces the sizes of built-up fractions and some larger characters. For instance, as a centered equation, the last one above becomes
