Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

3*x+2 == -4*x+9

⇒ algebra.equations.linear.balance.var-left-plus, term=4*x

7*x+2 == 9

⇒ algebra.equations.linear.balance.con-right-minus, term=2

7*x == 7

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

x == 1