Help with this circuit hw.

this is extra information provided.

True table

Now, a) Find the Boolean formula for x_i in terms of d1 d0 and b_i. Simplify the formula as much as you can. Clearly indicate your final formula for x_i,

b) Find the Boolean formula for c_in. Simplify the formula as much as you can. Clearly indicate your final formula for c_in.

c) Now connect the ripple-carry adder's inputs, x3 x2 x1 x0, to d1 d0 and b3 b2 b1 b0 according to your formula from the previous step. Then, connect c_in to d1 d0 and any b_i you may need, according to your formula for c_in from above.

Logic Unit (ALU) that adds, subtracts, decrements and increments, in Logisim a3 xl xl l add/sub c out s3 so Combined Adder/Subtractor Logic Unit (ALU) that adds, subtracts, decrements and increments, in Logisim a3 xl xl l add/sub c out s3 so Combined Adder/Subtractor