Answer:
x = -12
Step-by-step explanation:
To solve an equation, you want to "undo" what has been done to the variable. Here, it has been multiplied by -1 and that result added to 7. In general, you want to "undo" these operations <em>in reverse order</em>.
First, you need to subtract 7 to undo the addition of 7. Of course, anything you do to one side of the equation is also done to the other side:
7 -x -7 = 19 -7
-x = 12 . . . . . . . . simplify
Now, you want to undo the multiplication by -1. Multiplication (or division) by -1 will take care of that:
(-1)(-x) = (-1)(12)
x = -12 . . . . . . . . simplify
The solution is x = -12.
