>>12248218" = " means it's a scale that is, by definition, in balance
just keep doing the same thing to both sides and it will remain in balance
d-8=6 | add 8 to both sides
d-8+8=6+8 | clean up
d=14
notice that after a while, it becomes a reflex that if you move something to the other side it always works if you change its sign
