a(c+b)=d
First, let's apply the Distributive Property
ac + ab = d
Now, subtract both sides by ab
ac + ab - ab = d - ab
ac = d - ab
Divide both sides by a to isolate the c on the left side
ac/a = (d - ab)/a
c = (d - ab)/a
Due to poor math text formatting, it is hard to determine the answer, but I would assume it's A.