Răspuns :
a) f+r=18,
r=f+8⇒f+f+8=18⇒2f=10⇒f=5
r=5+8=13
b)c+d=25
d=c-17
c+c-17=25
2c=42
c=21
d=4
c)n+(n+1)+(n+2)=33
3n+3=33
n=10
nr sunt:10,11,12
d) 2n+(2n+2)+(2n=4)=30
6n=30-6=24
n=4
nr sunt:4,6,8
r=f+8⇒f+f+8=18⇒2f=10⇒f=5
r=5+8=13
b)c+d=25
d=c-17
c+c-17=25
2c=42
c=21
d=4
c)n+(n+1)+(n+2)=33
3n+3=33
n=10
nr sunt:10,11,12
d) 2n+(2n+2)+(2n=4)=30
6n=30-6=24
n=4
nr sunt:4,6,8
1.a+b=18 Varianta II
a=b+8 bI--------I
b+8+b=18⇒2b=10 a I--------I+8
b=5 18-8=10
a=5+8=13 10:2=5 fuste
rochii:13 5+8=13 rochii
fuste:5
2.a+b=25 Varianta II
a=b-17 carti I--------------I
b-17+b=25⇒2b=25+17⇒b=42/2 dictionare I--------I- 17
b=21 25+17=42
a=21-17 42:2=21 carti
a=4 25-21=4 dictionare
dictionare:4
carti:21
3) x+(x+1)+(x+2)=33 x-primul nr
3x=33-3 x+1- al doilea nr. consecutiv
x=30/3 x+2-al treilea nr.
x=10
nr.consecutive sunt:10, 11, 12
4) x+(x+2)+(x+4)=30
3x=30-6
x=24/3
x=8
nr.pare consecutive sunt: 8, 10, 12
a=b+8 bI--------I
b+8+b=18⇒2b=10 a I--------I+8
b=5 18-8=10
a=5+8=13 10:2=5 fuste
rochii:13 5+8=13 rochii
fuste:5
2.a+b=25 Varianta II
a=b-17 carti I--------------I
b-17+b=25⇒2b=25+17⇒b=42/2 dictionare I--------I- 17
b=21 25+17=42
a=21-17 42:2=21 carti
a=4 25-21=4 dictionare
dictionare:4
carti:21
3) x+(x+1)+(x+2)=33 x-primul nr
3x=33-3 x+1- al doilea nr. consecutiv
x=30/3 x+2-al treilea nr.
x=10
nr.consecutive sunt:10, 11, 12
4) x+(x+2)+(x+4)=30
3x=30-6
x=24/3
x=8
nr.pare consecutive sunt: 8, 10, 12