Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

3*x-7 == -4*x
algebra.equations.linear.balance.var-left-plus, term=4*x
7*x-7 == 0
algebra.equations.linear.balance.con-right-plus, term=7
7*x == 7
algebra.equations.linear.balance.scale-to-one, factor=7
x == 1