1) 5^2x = 5^3

  2x = 3

  x = 3/2

  x = 1,5

2) log2(2x-4)= 3, x > 2

   log2(2(x - 2)) = 3

   log2(2)+ log2(x - 2) = 3

   1+ log2(x - 2) = 3

   log2(x - 2) = 2

   x - 2 = 2^2

   x - 2 = 4

   x = 6

3) 2x - 1 = x^2 - 4x + 4

   2x - 1 -x^2 + 4x - 4 = 0

   6x - 5 -x^2 = 0

   -x^2 + 6x - 5 = 0

   x^2 - 6x + 5 = 0

   x^2 - x - 5x + 5 = 0

   x(x - 1) - 5(x - 1) = 0

   (x - 1)(x - 5) = 0

   x = 5

 Четвертое не знаю