Ответ:

1)7.5a²+35ab

2)3x²+32x-20

3)-x²-4x+32

4)-3y²-11y+4

5)-6,3a+58,8ab-8.4a²

6)8x²-10x

7)b²-14b-32

8)b²+2b+48

9)6.3a-58.8ab+8.4a²

10)6x²-5x-4

11)126a-42ax+9-3x

12)m²-n²

Verified answer

[tex]2.5a(3a + 14b) = 7.5 {a}^{2} + 35ab[/tex]

[tex](x - 10)(2 - 3x) = 2x - 3 {x}^{2} - 20 + 30x = - 3 {x}^{2} + 32x - 20[/tex]

[tex](x + 8)(4 - x) = 4x - {x}^{2} + 32 - 8x = - {x}^{2} - 4x + 32[/tex]

[tex]( - 3y + 1)(4 + y) = - 12y - 3 {y}^{2} + 4 + y = - 3 {y}^{2} - 11y + 4[/tex]

[tex] - 4.2a(1.5 - 14b + 2a) = - 6.3a + 58.8ab - 8.4 {a}^{2} [/tex]

[tex](4x + 1)(2x - 3) = 8 {x}^{2} - 12x + 2x - 3 = 8 {x}^{2} - 10x - 3[/tex]

[tex](b + 2)(b - 16) = {b}^{2} - 16b + 2b - 32 = {b}^{2} - 14b - 32[/tex]

[tex](b - 6)(b + 8) = {b}^{2} + 8b - 6b - 48 = {b}^{2} + 2b - 48[/tex]

[tex]4.2a(1.5 - 14b + 2a) = 6.3a - 58.8ab + 8.4 {a}^{2} [/tex]

[tex](3x - 4)(2x + 1) = 6 {x}^{2} + 3x - 8x - 4 = 6 {x}^{2} - 5x - 4[/tex]

[tex](42a + 3)(3 - x) = 126a - 42ax + 9 - 3x[/tex]

[tex]( - m + n)( - m - n) = {m}^{2} - {n}^{2} [/tex]