Question

помогите пожалуйста я не успеваю всё сделать​

Answer 1

1)

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

2)

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

3)

$(m - 2n)(m + 2n) = {m}^{2} - 4 {n}^{2}$

4)

$( \frac{1}{2} a - 3)( \frac{1}{2} a + 3) = \frac{1}{4} {a}^{2} - 9$

5)

$( \frac{5}{9} ax + \frac{3}{4} bc)( \frac{5}{9} ax - \frac{3}{4} bc) = \frac{25}{81} {a}^{2} {x}^{2} - \frac{9}{16} {b}^{2} {c}^{2}$

6)

$4(a - 3)(3 + a) = 4( {a}^{2} - 9) = 4 {a}^{2} - 36$

7)

$0.1b(y - 9)(9 + y) = 0.1b( {y}^{2} - 81) = 0.1b {y}^{2} - 8.1b$

8)

$(a + y)( - a - y) = - (a + y)(a + y) = - {(a + y)}^{2} = - ( {a}^{2} + 2ay + {y}^{2} ) = \\ \\ = - {a}^{2} - 2ay - {y}^{2}$

9)

$( - x + y)(y + x) = {y}^{2} - {x}^{2}$

10)

$( - m - n)(m - n) = - (m + n)(m - n) = - ( {m}^{2} - {n}^{2} ) = {n}^{2} - {m}^{2}$

11)

$( - 6b - 1)(6b - 1) = - (6b + 1)(6b - 1) = - (36 {b}^{2} - 1) = 1 - 36 {b}^{2}$