We are to simplify:
(2x + 3)2 - 4(2x + 3) - 12 = 0
(2x + 3) . 2 -4(2x + 3) -12 = 0
Let's add similar elements:
2(2x + 3) - 4(2x + 3) = -2(2x + 3)
Add 12 to both sides
-2(2x + 3)- - 12 + 12 = 0 + 12
let's simplify.
-2(2x + 3) = 12
Divide both sides by -2
-2(2x + 3) = 12
-2 -2
2x + 3 = -6
subtract 3 from both sides
2x + 3 - 3 = -6 - 3
2x = -9
Divide both sides by 2
2x/2 = -9/2
x = -9/2