You have to move all terms involving the variable on one side, and all constant terms on the other side.
To move a term from a side to the other, you have to change its side.
So, for example, if you move 4x from left to right, it will become -4x (you're actually subtracting 4x from both sides):
[tex] 1 = -5+7x-4x = -5+3x [/tex]
Similarly, add 5 to both side to get
[tex] 1+5 = 3x \iff 3x = 6 [/tex]
Finally, divide both sides by 3:
[tex] x = 2 [/tex]
