Exercise algebra.equations.linear.balance
Description
Solve a linear equation using only balance rules.
Derivation
![](http://ideas.cs.uu.nl/images/external.png)
3*x == -21+6*x
⇒ algebra.equations.linear.balance.var-left-minus, term=6*x-3*x == -21
⇒ algebra.equations.linear.balance.scale-to-one, factor=-3x == 7