Begin by subtracting #5# from both sides to get the #z# term by itself. This gives you:
#2z>=1470#
Then divide by #2# on both sides to get #z# by itself. This will give you:
#color(red)(z>=735)#
This can be checked by picking a value greater than #735# and a value less than #735# and testing them against the original inequality.
For example, let's try #600# and #800#.
#600# is less than #735#, so the inequality shouldn't work.
#2z+5>=1475#
#2(600)+5>=1475#
#1205>=1475# -- which is not true.
As for #800#, this should work because it is greater than #735#.
#2z+5>=1475#
#2(800)+5>=1475#
#1605>=1475# -- which is true.
