Китайская задача. может кто знает как решить..А+В=8С-Д=6=  =13 8

a + b = 8 => a = 8 - b b + d = 8 => d = 8 - b, = d a + c = 13 => a = 13 - c c - d = 6 => d = c - 6  a = d c - 6 = 13 - c => 2c = 19 => c = 9.5 : A+b=8,c-d=6,a+c=13,b+d=8.. a + b = 8 => a = 8 - b b + d = 8 => d = 8 - b,  a = d a + c = 13 => a = 13 - c c - d = 6 => d = c - 6  a = d c - 6 = 13 - c => 2c = 19 => c = 9.5 a + b = 8, (1) c - d = 6, (2) a + c = 13, (3) b + d = 8. (4) (1), (2), (3)  (4)  2a + 2b + 2c = 8 + 6 + 13 + 8 = 35, or a + b + c = 17.5.   c = 17.5 - 8 = 9.5..  b = 17.5 - 13 = 4.5.  (1) a = 8-b = 8-4.5 = 3.5,  (4) d = 8-b = 8-4.5 = 3.5.  a = 3.5, b = 4.5, c = 9.5, d = 3.5.