Exercise algebra.manipulation.rational.simplify

Description
simplify a rational expression (with a variable in a divisor)

Derivation

2/(x*y)-7/(5*y)

⇒ algebra.equations.rational.rational-scale

10/(5*x*y)-7*x/(5*x*y)

⇒ algebra.equations.rational.rational-plus

(10-7*x)/(5*x*y)