Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

2/3*x == 1/5*x+7/5

⇒ algebra.equations.linear.balance.remove-div, factor=15

10*x == 3*x+21

⇒ algebra.equations.linear.balance.var-left-minus, term=3*x

7*x == 21

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

x == 3