Your commission must be equal to the sum of the 10% of the value of the rug and the 15% of the value of the furniture and equate this to the value of your commission. Translate this to a mathematical equation, you would get,
Commission = (10%) (value of rugs) + (15%) (value of furniture).
substituting the known values,
5000 =.1 * x + .15 * 12500.
Now it's a matter of finding for x. You should get,