Ответ:

Пошаговое объяснение:

1) 3(x + 5) + 7x = 3x + 15 + 7x = 10x + 15

при x = 4;

10x + 15 = 10*4 + 15 = 40+15=55

2) 12(4 + y) - 5y = 48 + 12y - 5y = 48 + 7y

при у = 2;

48+7y = 48+7*2=48+14=62

3) 6x + 4(2x+7) = 6x + 8x + 28 = 14x + 28

при х=3;

14x + 28 = 14*3 + 28 = 42 + 28 = 70

4) 9y + 2(6y + 5) = 9y + 12y + 10 = 21y + 10

при y = 7;

21y + 10 = 21*7 + 10 = 147+10=157

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7(x + 8) - 25 = 66

7(x + 8) = 66+25

7(x + 8) = 91

x + 8 = 91:7

x + 8 = 13

x = 13-8

x = 5

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9(5x + 13) = 252

5x + 13 = 252 : 9

5x + 13 = 28

5x = 28 - 13

5x = 15

x = 15:5

x = 3

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15(13x - 7) = 285

13x - 7 = 285 : 15

13x - 7 = 19

13x = 19+7

13x = 26

x = 26:13

x = 2

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(y + 46) : 3 = 18

y + 46 = 18*3

y + 46 = 54

y = 54 - 46

y = 8

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(2x + 39) : 5 = 13

2x + 39 = 13*5

2x + 39 = 65

2x = 65 - 39

2x = 26

x = 26:2

x = 13

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182 : (x - 15) = 14

x - 15 = 182 : 14

x - 15 = 13

x = 13+15

x = 28