2x+5=4x-7 that's the equation.
The number is 6, I believe. The way to do that is...
You have to put 2x on the other side
then add 7 to both sides
then divide both sides by 2
here is the worked out thing ↓↓↓
2x+5=4x-7
-2x -2x
---------------
5=2x-7
+7 +7
------------
12=2x
/2 /2
--------
6=x