First, add #color(red)(5.3)# to each side of the inequality to isolate the #b# term while keeping the inequality balanced:
#-1.2b - 5.3 + color(red)(5.3) >= 1.91 + color(red)(5.3)#
#-1.2b - 0 >= 7.21#
#-1.2b >= 7.21#
Now, divide each side of the inequality by #color(blue)(-1.2)# 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:
#(-1.2b)/color(blue)(-1.2) color(red)(<=) 7.21/color(blue)(-1.2)#
#(color(blue)(cancel(color(black)(-1.2)))b)/cancel(color(blue)(-1.2)) color(red)(<=) -6.008bar3#
#b color(red)(<=) -6.008bar3#
