>>13365334The right aproximation of yours was the second. The equation should be worked equally on both sides.
The expression X + 3 = 7 is telling you that some X unit is added with 3 units, giving you a ressult of 7 units. In order to know the value of X, you have to let it be alone on one side of the equation So that X = [something] The way you do that is to make an operation on that side of the equation.
So X + 3 - 3 translates to X + 0 now being just X alone on that side but that isn't that right, because now that we messed up with one side of the equation, we created an unbalance, luckly we know how to solve that new issue.
Since the equation means that something is equal to other something, then, when we mess with one side of it, we must also mess ["equally"] on the other side. So if a = b , and i add 3 to a, then a + 3 =/= b that is a + 3 is not equal anymore to b, but if i also add 3 to b, then i can say that a +3 = b + 3.
By the previous principle mentioned then your problem 3 + x = 7 can be solved by doing this.
> 3 + x= 7//Now we substract 3 on both sides to let X alone on one side, but keep the equation balanced on the other
> 3 + x - 3 = 7 - 3 > 0 + x = 4> x = 4 
