(450 – 300) - х = 450 ,
150 - х = 450,
х = 150 - 450,
х = - 300,
x - (315 – 245) = 526 ,
х - 70 = 526,
х = 526 + 70,
х = 596,
(859 – 259) : x = 200,
600 : х = 200,
х = 600 : 200,
х = 3
