Step 1) Subtract #color(red)(0.03)# from each side of the inequality to isolate the #a# term while keeping the inequality balanced:
#0.18 - color(red)(0.03) >= 0.05a + 0.03 - color(red)(0.03)#
#0.15 >= 0.05a + 0#
#0.15 >= 0.05a#
Step 2) Divide each side of the inequality by #color(red)(0.05)# to solve for #a# while keeping the inequality balanced:
#0.15/color(red)(0.05) >= (0.05a)/color(red)(0.05)#
#3 >= (color(red)(cancel(color(black)(0.05)))a)/cancel(color(red)(0.05))#
#3 >= a#
To state the solution in terms of #a# we can reverse or "flip" the entire inequality:
#a <= 3#