Алгебра 8 класс учебник Макарычев, Миндюк ответы – номер 231

а) x + y + x − y/4 = x/1 + y/1 + x − y/4 = x ⋅ 4/1 ⋅ 4 + y ⋅ 4/1 ⋅ 4 + x − y/4 = 4x + 4y + x − y/4 = 5x + 3y/4
б) m + n − 1 + mn/n = m/1 + n/1 − 1 + mn/n = m ⋅ n/1 ⋅ n + n ⋅ n/1 ⋅ n − 1 + mn/n = mn + n² − 1 − mn/n = n² − 1/n
в) a − ab + ac + bc/a + b + c = a/1 − ab + ac + bc/a + b + c = a ⋅ (a + b + c)/1 ⋅ (a + b + c) − ab + ac + bc/a + b + c = a² + ab + ac − ab − ac − bc/a + b + c = a² − bc/a + b + c
г) a² − b² − a³ − b³/a + b = a²/1 − b²/1 − a³ − b³/a + b = a² ⋅ (a + b)/1 ⋅ (a + b) − b² ⋅ (a + b)/1 ⋅ (a + b) − a³ − b³/a + b = a³ + a²b − ab² − b³ − a³ + b³/a + b = a²b − ab²/a + b