The values of a.”,b, and c in equation’s standard form

For each proportion find the unknown number x 1/5/8=×/15

The label on a can of lemonade gives the volume as 12 fl 0z or 355ml verify that these two measurements are nearly equivalent

How do you figure out which order to do two step equations in? like which thing do you subtract/add/multiply/divide first? i understand that you do the opposite of whatever's shown on the opposite side, but when?