The inhabitants of planet Romeo, a remote planet in the milky way, use a number system which is similar to the decimal system used here on the earth, except that it has eleven distinct digits instead of the usual ten digits. The extra digit is an alien digit called x, which is inserted between the digits 7 and 8. Now 8 − 7 = 2 and x is the digit, which is equidistance from 7 and 8, i.e., x − 7 = 8 − x = 1. All the algebric signs and operations carry the same meaning as in the usual sense.
What is the decimal equivalent of the two digit number ‘9x’?