Exercise algebra.equations.linear.balance
Description
Solve a linear equation using only balance rules.
Derivation
-30 == -7*x-9
⇒ algebra.equations.linear.balance.con-left-plus, term=9-21 == -7*x
⇒ algebra.equations.linear.balance.scale-to-one, factor=-73 == x
⇒ algebra.equations.linear.flipx == 3