Раскрыть скобки: 31(4-z) 5(b+c+d) (5-25y)8
31(4-z) = 31*4-31*z = 124-31z 5(b+c+d) = 5*b+5*c+5*d = 5b+5c+5d (5-25y)8 = 5*8-25y*8 = 40-200y
31*4+31*-z=124-31z 5*b+5*c+5*d=5b+5c+5d 8*5+8*(-25y)=40-200y