remember you can do anything to an equation as long as you do it to both sides
ok, what I would do is undistribute that 2 from the parentahsese then divide both sides by 4 but that's too complex so
distribute, remember that a(b+c)=ab+ac
so
-8+8b=-4+4b+8
combine like terms
-8+8b=4b+4
minus 4b from both sides
-8+4b=4
add 8 to both sides
4b=12
divide both sides by 4
b=3