Make x the subject of the formula
16 = -2x - 1
Take -2x to the other side of the equation. Moving it to the other side will change its sign from - to +
16 + 2x = -1
Take 16 to the other side of the equation and its sign will change from + to -.
Note : If there is no sign with the number at the beginning of an equation it means that there is a plus there just like the 16 in this one, but if it is minus, it will be put there just like the -2x from the question
2x = -1 -16
2x = -17
Just like saying you owe your friend $1 and you owe another friend $17, altogether you owe $18.
Divide both sides by 2
2x/2 = -17/2
x = -17/2
You can leave your answer like this or convert it to mixed fraction or decimal
8 1/2 or 8.5