Respuesta :

12-3b<9 (subtract 12 from both sides)

-3b<-3 (divide by -3, but since you're dividing by a negative the sign flips)

b>1

If your getting b isolated you would start by subtracting 12 from both sides12 - 3b < 9     -----------------> -3b < -3-12          -12

Then, divide negative 3 from both sides (note: Dividing and multiplying negatives switches the direction of the < or > sign.

-3b < -3  ------------------> b > 1
/-3    /-3