Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

-4 == 7*x-12

⇒ algebra.equations.linear.flip

7*x-12 == -4

⇒ algebra.equations.linear.balance.con-right-plus, term=12

7*x == 8

⇒ algebra.equations.linear.balance.scale-to-one, factor=7

x == 8/7