Answer:
he used distribution method.
for step 1.as he distribute
2(x-1)=2x-2
Diffusions
Osmosis
Facilitated diffusion
Active transport
Basically, Benedict's test identifies the existence of aldehydes and alpha-hydroxy-ketones, also by hemiacetal, as well as those that take place in specific ketoses. Therefore, it is an alpha-hydroxy-ketone even if the ketose fructose is not strictly a reducing sugar, and provides a positive test since it is transformed into the mannose and aldoses glucose by the base inside the reagent.