Answer :

4cx - 5c = -12x + d
we can factor out the c, to get:
c(4x - 5) = -12x + d

divide both sides by (4x - 5) to get c
c = -12x + d 
      4x - 5

or you can use the same equation to get d
c(4x - 5) = -12x + d
add 12 x to both sides

d = c(4x - 5) + 12x