What's the easiest way to solve this problem

Question

-1.28 = Sigma^-1 (25 - Mu)
1.28 = Sigma^-1 (475 - Mu)

were Sigma and Mu are each different varialbes that are constant...

Thanks

Answer 1

Rewrite the equations as:
-1.28 =(25 - μ)/σ .... (1)
1.28 = (475 - μ)/σ .... (2)

Divide (2) by (1) to get
(475-μ)/(25-μ) = 1
Solve for μ and back substitute in (1) or (2).
μ=250, σ=175 approx.