Exercise algebra.equations.linear.balance

Description
Solve a linear equation using only balance rules.

Derivation

-1 == 8*x-20
algebra.equations.linear.balance.con-left-plus, term=20
19 == 8*x
algebra.equations.linear.balance.scale-to-one, factor=8
19/8 == x
algebra.equations.linear.flip
x == 19/8