ГДЗ до підручника «Алгебра» О.С. Істера. 7 клас

444. 1) (3а - 4b)2 - (3а + 4b)2 = 9а2 - 24ab + 16b2 - (9а2 + 24ab + 16b2) = 9а2 - 24ab + 16b2 - 9а2 - 24ab - 16b2 = -48ab;

2) (2а + 3b)2 + (а - 6b)2 = 4а2 + 12ab + 9b2 + a2 - 12ab + 36b2;

3) a(2a - 1)2 - 4a(a + 5)2;

4) 12m2 - 3(2m - n)2 - 12mn.

445. 1) (7a + 9b)2 - (7a - 9b)2 = 49a2 + 126ab + 81b2 - 49a2 + 126b - 81b2 - 252ab;

2) (10a - 3b)2 + (6a + 5b)2 - 100a2 - 60ab + 9b2 + 36a2 + 60ab + 25b2 = 136a2 + 61b2;

3) 18x2 - 12xy - 2(3х - y)2 = 18x2 - 12xy - 2(9x2 - 6xy + y2) = 18x2 - 12xy - 18x2 + 12xy - 2y2 = -2y2;

4) a(9a - 1)2 - 81a(a - 2)2 = a(81a2 - 18a + 1) - 81a(a2 - 4a + 4) = 81a3 - 18a2 + a - 81a3 + 324a2 - 324a = 306a2 - 323a.

446. 1) (* + 2a)2 = b2 + 4ab + 4a2;

(b + 2a)2 = b2 + 4ab + 4a2;

2) (2b - *)2 = 4b2 + 9 - 12b;

(2b - 3)2 = 4b2 - 12b + 9;

3) (3a4 + *)2 = * + 30a4 + 25;

(3a4 + 5)2 - 9a8 + 30a4 + 25;

4) (5x2 - *)2 = 25x4 - * + 9m2;

(5x2 - 3m)2 = 25x4 - 30x2m + 9m2.

447. 1) (* - 7)2 = x2 - 14x + 49;

(x - 7)2 = x2 - 14x + 49;

2) (4p3 + *)2 = * + 9 + 24p3;

(4p3 + 3)2 = 16p6 + 9 + 24p3.

448. 1) (x - 2)(x + 1)2 = (x - 2)(x2 + 2x + 1) = x3 + 2x2 + x - 2x2 - 4x - 2 - x3 - 3x - 2;

2) (x + 1)(x - 5)2 = (x + 1)(x2 - 10x + 25) = x3 - 10x2 + 25x + x2 - 10x + 25 = x3 - 9x2 + 15x + 25.

449. 1) (a + b)2 + (a - b)2 = 2(a2 + b2); a2 + 2ab + b2 + a2 - 2ab - b2 = 2a2 + 2b2 = 2(a2 + b2);

2) m2 + n2 = (m + n)2 - 2mn = m2 + 2mn + n2 - 2mn = m2 + n2.

Попередня
Сторінка
Наступна
Сторінка

Зміст