Question

помогите срочно пожалуйста

Answer 1

Ответ:

1.

$1) {(x + 9)}^{2} = {x}^{2} + 2 \times x \times 9 + 81 = \\ = {x}^{2} + 18x + 81$

$2) {(3a - 8b)}^{2} = 9 {a}^{2} - 48ab + 64 {b}^{2}$

$3)(m - 7)(m + 7) = {m}^{2} - {7}^{2} = {m}^{2} - 49$

$4)(6a + 10b)(10b - 6a) = {(10b)}^{2} - {(6a)}^{2} = \\ = 100 {b}^{2} - 36 {a}^{2}$

2.

$1) {c}^{2} - 1 = (c - 1)(c + 1)$

$2) {x}^{2} - 4x + 4 = {x}^{2} - 2 \times 2 \times x + {2}^{2} = \\ = {(x - 2)}^{2}$

$3)25 {y}^{2} - 4 = {(5y)}^{2} - {2}^{2} = (5y - 2)(5y + 2)$

$4)36 {a}^{2} - 60 ab + 25 {b}^{2} = {(6a)}^{2} - 6a \times 2 \times 5b + {(5b)}^{2} = \\ = {(6a - 5b)}^{2}$

3.

$(x + 3)(x - 3) - {(x - 4)}^{2} = {x}^{2} - 9 - ( {x}^{2} - 8x + 16) = \\ = {x}^{2} - 9 - {x}^{2} + 8x - 16 = \\ = 8x - 25$