I need some help with this problem.

Marcie wants to enclose her yard with a fence. Her yard is in the shape of a rectangle attached to a triangle. The formula for the area of the enclosed space is A = lw + 0.5bh. Solve for b.

b = A divided by the quantity l times w plus 0.5 times h
b = The quantity A minus l times w all divided by 0.5 times h
b = A − lw − 0.5h
b = A + lw + 0.5h

Plz Help