Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

7/15*x-7/5 == 0

⇒ algebra.equations.linear.balance.remove-div, factor=15

7*x-21 == 0

⇒ algebra.equations.linear.balance.con-right-plus, term=21

7*x == 21

⇒ algebra.equations.linear.balance.scale-to-one, factor=7

x == 3