Question

5).Aflati X ,daca a+b=8 :
a)X+2a+2b=20
b)5a+5b-X=12
c)X+6=23+7a+7b


6).Scoateti factor comun:
a)6a-8b
b)3×9+4×9-7×2


7).Aflati numarul natural X,daca a-b=17:
a)X-2a+2b=11
b)2b-2a+X=45

Va rooog,repede!
Dau COROANA!​

Answer 1

Răspuns:

5)

a) x+2a+2b=20

x+2(a+b)=20

x+16=20

x=20-16=4

b) 5a+5b-x=12

5(a+b)-x=12

40-x=12

x=40-12=28

c) x+6=23+7a+7b

x+6=23+7(a+b)

x=-6+23+56

x=73

6)a) 6a-8b=2(3a-4b)

b) 3*9+4*9-7*2=9(3+4)-7*2

=9*7-7*2=7(9-2)=7*7=49

7)

a)x-2a+2b=11/*(-1)

-x+2a-2b=-11

-x+2*17=-11

-x=-34-11

X=45

b) 2b-2a+x=45

2(b-a)+x=45

34+x=45

x=11

Answer 2

Răspuns:

a) x+2a+2b=20

x+2(a+b)=20

x+2·8=20

x=20-16=>x=4

b) 5a+5b-x=12

5(a+b)-x=12

40-x=12

x=40-12=>x=28

c) x+6=23+7a+7b

x+6=23+7(a+b)

x=23-6+7·8

x=17+56=>x=73

6) a) 6a-8b=2(3a-4b)

b) 3·9+4·9-7·2=9·(3+4)-7·2

=9·7-7·2=7·(9-2)=7·7=49

7)  a) x-2a+2b=11

x-2·(a-b)=11

x-2·17=11

x-34=11=>

x=34+11=>x=45

b) 2b-2a+X=45

2(a-b)+x=45

2·17+x=45

x=45-34=>x=11