Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

2 == 7+2*x
algebra.equations.linear.balance.con-left-minus, term=7
-5 == 2*x
algebra.equations.linear.balance.scale-to-one, factor=2
-5/2 == x
algebra.equations.linear.flip
x == -5/2