subtract "2x" to "4x + 1" and that'll leave -5 by itself and leave 2x+1 on the left and -5 on the right then subtract -1 to -5 and it'll add up to -6 then after that you'd divide 2x to -6 and get -3 and it'll leave 'x' by itself so therefore X = -3
I like to think of the - or under as the less likely to happen like a cat beating up a bear u don’t want to put your money on the cat so everyone puts there money on the bear making the bear the over and the cat the under