Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

-4 == -2*x

⇒ algebra.equations.linear.flip

-2*x == -4

⇒ algebra.equations.linear.balance.negate

2*x == 4

⇒ algebra.equations.linear.balance.scale-to-one, factor=2

x == 2