2.4

3: Start by solving for b.

12: Multiply by 3 to cancel dividing by 3.

15: Start by distributing the -6.

19: Combine the variable terms on one side and the constant terms on the other.

29: Undo addition or subtraction before undoing multiplication or division.

31: Start with an equation with a 20x term in it.

33: The area of a rectangle is its length times its width.

41: Six times y is 6y.