Question

What is x?

2x - x + 7 = x + 3 + 4

Answer 1

First, simplify by adding common variables (numbers or letters)
x+7 = x+7
You can stop here, because this is always true.  So you can plug in any number for x.  The answer is all the numbers in the world, ever.

Answer 2

x is equal to 1 becuz 2x-x equals x+7=x+7 then divide 7 by itself and it's 1