Question

exercițiile 5, 6 ,7 si 8 va rooog urgent!!!!!

Answer 1

sper ca te.am ajutat

Answer 2

Răspuns

Explicație pas cu pas:

5)

a × 4 / 9 = 32 / 81

a = ( 32 / 81 ) : ( 4 / 9 )

a = ( 32 / 4 ) x ( 9 / 81 )

a = 8 x 1 / 9

a = 8 / 9 → fractia

Verific;   8 / 9  ×  4 / 9 = ( 8 x 4 ) / ( 9 x 9 ) = 32 / 81

___________________________________________

b)  

b × 9 / 5 = 4 / 3

b = ( 4 / 3 ) : ( 9 / 5 )

b = ( 4 / 3 ) × ( 5 / 9 )

b = 20 / 27

_______________________

6)

a)   → introduc intregii in fractie

3 intregi si 1 / 5 = ( 3 x 5 + 1 ) / 5 = 16 / 5

2 intregi si 1 / 6 = ( 2 x 6 + 1 ) / 6 = 13 / 6

( 31 / 12 ) : (  16 / 5  -  13 / 6 ) =

= ( 31 / 12 ) : ( 96 / 30 - 65 / 30 ) =

= ( 31 / 12 ) × ( 30 / 31 ) =

= ( 30 : 6 ) / ( 12 : 6 ) =

= 5 / 2 =

= 2 intregi si 1 / 2

_______________________

b)  

( 7 / 34 + 1 / 17 ) :  72 / 17 =

= ( 7 / 34 + 2 / 34 ) × 17 / 72 =

= ( 9 / 34 ) × 17 / 72 =

= 1 / ( 2 × 8 ) =

= 1 / 16

__________________

c)

( 16 / 5 - 5 / 2 ) : ( 7 / 6 + 7 / 3 ) =

= ( 32 / 10 - 25 / 10 ) : ( 7 / 6 + 14 / 6 ) =

= ( 7 / 10 ) × ( 6 / 21 ) =

= 3 / ( 5 × 3 ) =

= 1 / 5

_______________________________________________

7)

2 intregi si 3 / 10 = ( 2 x 10 + 3 ) / 10 = 23 / 10 → cablu de sarma

3 / 5 = ( 3 x 2 ) / ( 5 x 2 ) = 6 / 10

23 / 10 : 6 / 10 = 23 / 10  × 10 / 6 = 23 / 6 = 3 bucati intregi de cablu si rest 5 / 6

23 / 10 - 3 × 6 / 10 = 5 / 10 → lungimea portiunii ramase

____________________________________________

8)   26 ecusoane

7 intregi si 1 / 2 = ( 7 x 2 + 1 ) / 2 = 15 / 2 = 7,5 cm → lungimea ecusonului

200 cm : 7, 5 = 26 ecusoane si un rest de 0,(6)

sau:   200 : 15 / 2 = 200 ×  2 / 15 = 80 / 3 = 26 intregi si  2 / 3 ( restul )

26 intregi → reprezinta numarul ecusoanelor

2 / 3 → restul