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