We know the only number that gets us back to 0 after subtracting 4 is 4, because 4-4=0. The square root of 4 is 2. Hope my explanation wasn't too confusing!
1) add 4 to each side (the -4 will cancel) Then the equation will be X2= 4 Then cancel the 2 then do the same on the other side Now you got X=2 (but it could be - or +)
