Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

-9 == -9*x

⇒ algebra.equations.linear.flip

-9*x == -9

⇒ algebra.equations.linear.balance.negate

9*x == 9

⇒ algebra.equations.linear.balance.scale-to-one, factor=9

x == 1