Вправа 513 алгебра Бевз гдз 7 клас
№ 513
1) (a + b)2 = (a + b)2(a + b) = (a2 + 2ab + b2)(a + b) =
= a3 + a2b + 2a2b + 2ab2 + ab2 + b3 = a3 + 3ab2 – b + 3ab2 + b3;
2) (a – b)3 = (a – b)2(a – b) = (a2 – 2ab + b2)(a – b) =
= a3 – a2b – 2a2b + 2ab2 + ab2 – b3 = a3 – 3a2b + 3ab2 – b3.
а) x + 3 = (x + 3)3 = x3 + 9x2 + 27x + 27;
б) 4a + c = (4a + c)3 = x3 – 3x2y + 3xy2 – y3;
в) x – y = (x – y)3 = x3 – 3x2y + 3xy2 – y;
г) m + 2a = (m + 2a)3 = m3 + 6m2a + 12ma2 + 8a3.
вправи поруч
