First, expand the terms in parenthesis on each side of the equation:
#(2 xx x) + (2 xx 6) = (-2 xx x) - (-2 xx 4)#
#2x + 12 = -2x - (-8)#
#2x + 12 = -2x + 8#
Next, subtract #color(red)(12)# and add #color(blue)(2x)# to each side of the equation to isolate the #x# term while keeping the equation balanced:
#2x + 12 - color(red)(12) + color(blue)(2x) = -2x + 8 - color(red)(12) + color(blue)(2x)#
#2x + color(blue)(2x) + 12 - color(red)(12) = -2x + color(blue)(2x) + 8 - color(red)(12)#
#(2 + color(blue)(2))x + 0 = 0 - 4#
#4x = -4#
Now, divide each side of the equation by #color(red)(4)# to solve for #x# while keeping the equation balanced:
#(4x)/color(red)(4) = -4/color(red)(4)#
#(color(red)(cancel(color(black)(4)))x)/cancel(color(red)(4)) = -1#
#x = -1#