Question

Va rog dau coroana!❣️

Answer 1

Răspuns:

1)

3/7= a/21 》 a= 21×3/7

a = 63/7

a= 9

b+1/3=4/6

6(b+1) =3×4

6b+6 =12

6b= 12-6

6b =6

b =6÷6

b=1

2) 7/ 12 si 11/ 18

Numitor comun 36

7/ 12 ( aplificam cu 3) = 21/36

11/18 ( amplificam cu 2)= 22/36

21/36 < 22/36

21÷36= 0,58

22÷36= 0,61

3)

72/108 = ( simplificam prin 4) = 18/ 27 ( prin 9) = 2/3

250/350 = ( simplificam prin 100) = 25/35 ( prin 5) = 5/ 7

4) a)

14/15-2/15+17/20-7/20=

12/15+ 10/20 = ( aducem la același numitor 300)

240/300 + 150/300= 390/300 = 39/10

b)5/7-3/7+3/14+5/14= ( aducem la același numitor 14)

10/14 - 6/14 +3/14 +5/14=

4/14 +3/14 +5/14=

7/14+5/14=

12/14= 6/7

c)

8/15( 15/16÷3/8×3/4)=

8/15 × ( 15/16 ×8/3 ×3/4)=

8/15× ( 15/ 2 x 1/3 ×3/4)=

8/15 × (15/2× 1/4)=

8/15 × 15/8= 1

d)

9/10÷ [ ( 29/8-11/8)÷ 5/2]=

9/10÷ ( 18/8 ×2/5)=

9/10 ÷ ( 18/4 × 1/5)=

9/10÷ 18/ 20=

9/10× 20/18=

1/1× 2/2= 2/2=1

5)

telefon = 600 lei

ieftinire 10%

10/100×600= 60 de lei ( ieftinirea )

600 - 60 = 540 noul preț după ieftinire

Dacă se scumpește din prețul de 600 lei

10/100× 600 = 60 de lei ( scumpirea)

600 +60 lei= 660 de lei noul preț