Question

16. Rezolvați în mulțimea N ecuațiile: a) 9x+28=2755; 510+14x = 762; b) 5y-97= 943; 410-7y=151; c) 3(x+7)=75; 14(12-x) = 70; d) (82 + y):6=17; (y-33):9=305; e) 111+2x+29= 10³; 5x+52-31=30 –19; f) 5(y-2) +3=38; 9+2(14-y)=15. REPEDE DAU COROANA​

Answer 1

Răspuns:

a)

$9x + 28 = 2755 \\ 9x = 2755 - 28 \\ 9x = 2727 \\ x = 2727 \div 9 \\ x = 303$

510+14x=762

14x=762-510

14x=252

x=252÷14

x=18

b)5y-97=943

5y=943+97

5y=1040

y=1040÷5

y=208

410-7y=151

7y=410-151

7y=259

y=259:7

y=37

c)3×(x+7)=75

x+7=75÷3

x+7=25

x=25-7

x=18

14×(12-x)=70

12-x=70÷14

12-x=5

x=12-5

x=8

d)(82+y)÷6=17

82+y=17×6

82+y=102

y=102-82

y=20

(y-33)÷9=305

y-33=305×9

y-33=2745

y=2745+33

y=2778

e)111+2x+29=10³

2x=1000-140

2x=860

x=860÷2

y=430

5x+52-31=30

5x+52=30+31

5x+52=61

5x=61-52

5x=9

x=1,8

f)5×(y-2)+3=38

5(y-2)=38-3

5(y-2)=35

y-2=35÷5

y-2=7

y=7+2

y=9

9+2(14-y)=15

2(14y)=15-9

2(14y)=6

14y=6÷2

14y=3

y=3÷14

y=0,21