First, expand the terms in parenthesis on the left side of the equation by multiplying each term within the parenthesis by the term outside the parenthesis:
#color(red)(6)(x + 11) = 14x + 42#
#(color(red)(6) xx x) + (color(red)(6) xx 11) = 14x + 42#
#6x + 66 = 14x + 42#
Next, subtract #color(red)(6x)# and #color(blue)(42)# from each side of the equation to isolate the #x# term while keeping the equation balanced:
#-color(red)(6x) + 6x + 66 - color(blue)(42) = -color(red)(6x) + 14x + 42 - color(blue)(42)#
#0 + 24 = (-color(red)(6) + 14)x + 0#
#24 = 8x#
Now, divide each side of the equation by #color(red)(8)# to solve for #x# while keeping the equation balanced:
#24/color(red)(8) = (8x)/color(red)(8)#
#3 = (color(red)(cancel(color(black)(8)))x)/cancel(color(red)(8))#
#3 = x#
#x = 3#