при |x-9| = x-9:

x-9 = -5.9 + 3 + 4.1 + 7

x = -5.9 + 3 + 4.1 + 7 + 9

x = 17.2

при |x-9| = -x+9:

-x + 9 = -5.9 + 3 + 4.1 + 7

-x = -5.9 + 3 + 4.1 + 7 - 9

x = 5.9 - 3 - 4.1 - 7 + 9

x = 0.8