When the brackets are opened the equation becomes: -24x-18=-24x-18, so the two sides of the equation are exactly the same. The equation in the title is an identity not an equation so there's nothing to solve! The equation in the context is different, because minus has become plus in the second bracket. If we open the brackets in the equation in the context we get: -24x-18=-24x+18. We're left with -18=18, or 36=0, which isn't true for any value of x (the x terms cancel out). The only way to treat the two equations is as logical statements. The first equation is a true statement and the second equation is a false statement,