Алгебра 7 класс 12.1 12.2 12.3 чётные

12.1

1) +1

2)y+2x+6

3)3ab+9

4)23,8 +

12.2

1)41-89

2)85+29mn

3)21b+7

4)13,2kt+2,2z

13.2

1)27x+13y

2)9b-5a

3)-0,5m-7,2n

4)1,9k+8,8t

5) a - 9b

6) a +113d -

Объяснение:

12.3

1)(4x+8y)+(23x+5y) = 4x+8y+23x+5y = 27x+13y

2) (83a-91b) - (89a-100b) = 83a-91b-89a+100b = -5a+9b = 9b-5a

3) (1,5m - 4,2n) - (2m+3n) = 1,5m - 4,2n - 2m - 3n = -0,5m-7,2n

4) (5k+6t)+(2,8t-3,1k) = 5k+6t+2,8t-3,1k = 1,9k+8,8t

5) = = a - 9b

6) = a +113d -