Given that the value of an industrial machine has a decay factor of 0.75 per year, and after six years, it became $7,500 only, this would mean that the original value of the machine would be solved like this: 7500 = x(1-.75)^6
7500 = x(0.25)^6
7500 = x(0.00024414062)
7500 = 0.00024414062x
x = 30, 720, 000
Hope this answers your question.
