Алгебра 8 класс учебник Макарычев, Миндюк ответы – номер 78

а) b/a² − 1/a = b/a² − 1 ⋅ a/a ⋅ a = b/a² − a/a² = b − a/a²
б) 1 − x/x³ + 1/x² = 1 − x/x³ + 1 ⋅ x/x² ⋅ x = 1 − x/x³ + x/x³ = 1 − x + x/x³ = 1/x³
в) 1/2a⁷ + 4 − 2a³/a¹⁰ = 1 ⋅ a³/2a⁷ ⋅ a³ + (4 − 2a³) ⋅ 2/a¹⁰ ⋅ 2 = a³ + 8 − 4a³/2a¹⁰ = 8 − 3a³/2a¹⁰
г) a + b/a² + a − b/ab = (a + b) ⋅ b/a² ⋅ b + (a − b) ⋅ b/ab ⋅ b = ab + b² + a² − ab/a²b = a² + b²/a²b
д) 2a − 3b/a²b − 4a − 5b/ab² = (2a − 3b) ⋅ b/a²b ⋅ b − (4a − 5b) ⋅ a/ab² ⋅ a = 2a − 3b² − 4a² + 5ab/a²b = 2ab − 3b² − 4a²/a²b
е) x − 2y/xy² − 2y − x/x²y = (x − 2y) ⋅ x/xy² ⋅ x − (2y − x) ⋅ y/x²y ⋅ y = x² − 2xy - 2y² + xy/x²y² = x² − xy - 2y²/x²y²