[tex]\dfrac 27 >b +\dfrac 57\\\\\implies 2 > 7b +5~~~;[ \text{Multiplying both sides by 7}]\\\\\implies 2-5>7b\\\\\implies -3>7b\\\\\implies -\dfrac 37 >b\\\\\implies b<-\dfrac 37\\\\\\\text{Interval,}~ \left(-\infty, -\dfrac 37 \right)[/tex]