The property being used in this equation is the property of equality. If two expressions are equal to each other (x+z/y = a/b), then any operation performed on both sides of the equation must yield equal results. In this case, multiplying both sides of the equation by the same value (ay and bx=bz) results in equal expressions on each side of the equation, so the property of equality is being used.
This property is a fundamental concept in mathematics that is used to solve equations and to reason about the relationships between quantities. It is based on the idea that, if two quantities are equal, then any operation performed on them must yield equal results. This property is used frequently in algebra and other branches of mathematics to solve problems and to make logical deductions about quantities and relationships
If you want your questions answered put them in the correct category not college. This is not college. I will not answer anymore of your questions if you continue to mark them as college