Question

СРОЧНО! 7класс, алгебра​

Answer 1

Объяснение:

1. Да

0,6 × (-30) + 12 = -6

-18 + 12 = -6

-6 = -6

2. -3к + 17 = 30

-3к = 13

к = -4 1/3

3. 10 × (-0,25) + m = 6

-2,5 + m = 6

m = 8,5

4. 1) x + y = 5

3x + y = 7

y = 5 - x

3x + 5 - x = 7

y = 5 - x

2x = 2

y = 5 - x

x = 1

x = 1

y = 4

2) x - y = 0

x - 3y = 6

x = y

x - 3x = 6

x = y

-2x = 6

x = y

x = -3

x = -3

y = -3

3) 3m - 2n = 5

m + 2n = 15

m = 15 - 2n

4m = 20

m = 15 - 2n

m = 5

m = 5

2n = 15 - m

m = 5

2n = 10

m = 5

n = 5