Answer:
-k-h/r-s
When solving the goal is to get x on one side and not x on the other.
rx + h = sx - k
rx - sx + h = -k <------- subtract sx from both sides
rx - sx = -k - h <-------subtract h from both sides
x (r - s) = -k -h <------factor out x which is in both rx and sx
x = - k - h / r - s <-------divide by r-s on both sides
