First, expand the term within parenthesis by multiplying each term within the parenthesis by the term outside the parenthesis:
#-6v + color(red)(8)(v + 3) = 8#
#-6v + (color(red)(8) xx v) + (color(red)(8) xx 3) = 8#
#-6v + 8v + 24 = 8#
Next, combine like terms on the left side of the equation:
#(-6 + 8)v + 24 = 8#
#2v + 24 = 8#
Then, subtract #color(red)(24)# from each side of the equation to isolate the #v# term while keeping the equation balanced:
#2v + 24 - color(red)(24) = 8 - color(red)(24)#
#2v + 0 = -16#
#2v = -16#
Now, divide each side of the equation by #color(red)(2)# to solve for #v# while keeping the equation balanced:
#(2v)/color(red)(2) = -16/color(red)(2)#
#(color(red)(cancel(color(black)(2)))v)/cancel(color(red)(2)) = -8#
#v = -8#