First, add #color(red)(4.2)# to each side of the inequality to isolate the #b# term while keeping the inequality balanced:
#color(red)(4.2) - 4.2- 1.1b <= color(red)(4.2) + 2.4#
#0 - 1.1b <= 6.6#
#-1.1b <= 6.6#
Now, divide each side of the inequality by #color(blue)(-1.1)# to solve for #b# while keeping the inequality balanced. However, because we are multiplying or dividing an inequality by a negative term we must reverse the inequality operator:
#(-1.1b)/color(blue)(-1.1) color(red)(>=) 6.6/color(blue)(-1.1)#
#(color(blue)(cancel(color(black)(-1.1)))b)/cancel(color(blue)(-1.1)) color(red)(>=) -6#
#b >= -6#
