/2/3)×(-1/1/5)+x=0,5 /14)×21/25-y=3/3/4

Решение, при -6/2/3 = -2/3, а не -6/(2/3) = -9:

1) -6/2/3 * -1/1/5 - 1/2 + x = 0

  -3/3 * -1/5 - 1/2 = -x

  2(-1 * -1/5 - 1/2) = -x*2

  2/5 - 1 = -2x

  (-5+2)/5 = -2x

  -3/5 = -2x

  x = 3/10

  x = 0.3

2) (-5*21)/(14*25) - 3/3/4 = y

   (-1*21)/(14*5) - 3/3/4 = y

   (-1*3)/(2*5) - 3/3/4 = y

   -3/10 - 1/4 = y

   ((-3*4) - (1*10)) / 40 = y

   (-12 - 10)/40 = y

   y =  -22/40

   y = -11/20