3 - x = 12

Question

what is the value of x?

Answer 1

You can move -x to the right side of the = and 12 to the left side of the equal. After you do that, this becomes.

3-12= x

Notice when you move, this changes the + or - sign.

so x = -9

 

Answer 2

3 - x = 12

Add x to both sides

3 - x + x = 12 + x

3 = 12 + x               (- x and + x cancel each other out)

Subtract 12 from both sides

3 - 12 = 12 + x - 12

-9 = x                  (3 + -12 = -9)

 

 

 

Answer 3

Ok, we need to isolate x and there are two ways to do this. First, subtract 3 from both sides.

-3 + 3 - x = 12 - 3.

The two 3's on the left cancel and we have

-x = 9

Now, we multiply both sides by -1 so that x is by itself and we have x = -9!