1. Write the equation: d(-3 + x) = kx + 9 2. "Open" the parenthesizes: -3d + dx = kx + 9 3. Take kx to the left side, -3d to the right, everything with different sign (+ replace with - when transferring, - replace with +): dx - kx = 9 + 3d 4. Factor x in the left side: x(d - k) = 9 + 3d 5. Finally, divide the whole equation by (d - k): x = (9 + 3d)/(d - k) That's the final answer. Good luck!
