Exercise algebra.equations.linear.balance
Description
Solve a linear equation using only balance rules.
Derivation
![](http://ideas.cs.uu.nl/images/external.png)
-x-9 == -4
⇒ algebra.equations.linear.balance.con-right-plus, term=9-x == 5
⇒ algebra.equations.linear.balance.scale-to-one, factor=-1x == -5