First, expand the terms in parenthesis on the right side of the inequality by multiplying each term within the parenthesis by the term outside the parenthesis:
#36 <= color(red)(12)(1/3z + 2/3)#
#36 <= (color(red)(12) xx 1/3z) + (color(red)(12) xx 2/3)#
#36 <= 4z + 8#
Next, subtract #color(red)(8)# from each side of the inequality to isolate the #z# term while keeping the inequality balanced:
#36 - color(red)(8) <= 4z + 8 - color(red)(8)#
#28 <= 4z + 0#
#28 <= 4z#
Now, divide each side of the inequality by #color(red)(4)# to solve for #z# while keeping the inequality balanced:
#28/color(red)(4) <= (4z)/color(red)(4)#
#7 <= (color(red)(cancel(color(black)(4)))z)/cancel(color(red)(4))#
#7 <= z#
To put this solution in terms of #z# we can reverse or "flip" the inequality:
#z >= 7#