Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

15 == -2*x-5

⇒ algebra.equations.linear.balance.con-left-plus, term=5

20 == -2*x

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

-10 == x

⇒ algebra.equations.linear.flip

x == -10