Корень уравнения
3/4k-12,5=9/8k-1/8

3/4k - 12,5 = 9/8k - 1/8
3/4k - 25/2 = 9/8k - 1/8
6k - 100 = 9k - 1
6k - 9k = -1 + 100
-3k = -1 + 100
-3k = 99
k = 99 : (-3)
k = -33