First, expand the terms in parenthesis on the right side of the equation by multiplying each term in parenthesis by the term outside the parenthesis:
#7x + 29 = color(red)(4)(x + 8)#
#7x + 29 = (color(red)(4) xx x) + (color(red)(4) xx 8)#
#7x + 29 = 4x + 32#
Next, subtract #color(red)(29)# and #color(blue)(4x)# from each side of the equation to isolate the #x# term while keeping the equation balanced:
#-color(blue)(4x) + 7x + 29- color(red)(29) = -color(blue)(4x) + 4x + 32 - color(red)(29)#
#(-color(blue)(4) + 7)x + 0 = 0 + 3#
#3x = 3#
Now, divide each side of the equation by #color(red)(3)# to solve for #x# while keeping the equation balanced:
#(3x)/color(red)(3) = 3/color(red)(3)#
#(color(red)(cancel(color(black)(3)))x)/cancel(color(red)(3)) = 1#
#x = 1#