8ax+4b = 4cx+d

Answer 1

i guess u wanna determine x in terms of a,b,c

8ax+4b=4cx+d

8ax-4cx=d-4b

x(8a-4c)=(d-4b)
x=(d-4b)/(8a-4c)

Answer 2

correct, as long as a does not equal 1/2 c. Division by zero is never allowed.