Solve for x-
(3/7)^(1−2x)/2 = 12 19/27

Hint:

In Mathematics, lets say, "a" represents a number and "n" is the number of times that number is to be multiplied with itself, in order to get a desired result. Then, such result can be written as an, where a is called the base and n is its power/ exponent.
an = a × a × ... × a                    n times.
2. A fraction represented with its quotient and remainder is a mixed fraction.
In the given sum, quotient = 12, remainder = 19 & Divisor = 27.
∴ The given mixed fraction can be written as- (Quotient × Divisor + Remainder) / Divisor = (12×27) + 19 / 27 = 343/27