Question

СРОЧНО ДАЮ 100 БАЛОВ!!! 1) (c - 7) * (c + 2) 2) (5c + 2) * (1 - 2c) 3) (3c - 2d) * (d - c) 4) (5c + 8) * (2 - 9c) 5) (a+b) * (3a - b + 2) 6) (x^2 + 1) * (4-x^2) 7) (5 - x) (5+x) 8)(5 - x) (5 - x)

Answer 1

Ответ:

1) (c-7)(c+2) = c*c+2c-7c-7*2 = c²+2c-7c-7*2 = c²-5c-14

2) (5c+2)(1-2c) = 5c-5c*2c+2-2*2c = 5c-10c²+2-4c = c-10c²+2 = -10c²+c+2

3) (3c-2d)(d-c) = 3cd-3c*c-2d*d-2d(-c) = 3cd-3c²-2d²+2cd = 5c-3c²-2d²

4) (5c+8)(2-9c) = 5c*2-5c*9c+8*2-8*9c = 10c-45c²+16-72c = -62-45c²+16 =  

= -45c²-62c+16

5) (a+b)(3a-b+2) = a(3a-b+2)+b(3a-b+2) = 3a²-ab+2a+3ab-b²+2b =

=3a²+2ab+2a-b²+2b

6) (x²+1)(4-x²) = 4x²-x²*x²+4-x²  = 4x²-x^4+4 = -x^4+3x²+4

7) (5-x)(5+x) = 5²-x² = 25-x²

8) (5-x)(5-x) = (5-x)²

Answer 2

1. (c - 7) * (c + 2) = c^2 - 7c + 2c - 14 = c^2 - 5c - 14

2. (5c + 2) * (1 - 2c) = 5c - 10c^2 + 2 - 4c = -10c^2 + c - 2

3. (3c - 2d) * (d - c) = 3c*d - 3c^2 - 2d^2 + 2cd

4. (5c + 8) * (2 - 9c) = 10 - 45c^2 + 16 - 72c = -45c^2 - 72c + 26

5. (a+b) * (3a - b + 2) = 3a^2 - ab + 2a + 3ab - b^2 + 2b = 3a^2 + 2a + 2b + 2ab - b^2

6. (x^2 + 1) * (4 - x^2) = 4x^2 - x^4 + 4 - x^2 = -x^4 + 3x^2 + 4

7. (5 - x) * (5 + x) = 25 - x^2

8. (5 - x) * (5 - x) = 25 - 10x + x^2