Question

tote exercitile va rog va implor

Answer 1

1.
a+b+c=45
b=2a
c=b+15=2a+15
a+2a+2a+15=45
5a+15=45 |-15
5a=45-15
5a=30
a=6
b=2·6
b=12
c=12+15
c=27

2.
l=L/3⇒L=3l
L=l+8
Egalezi relatiile
3l=l+8
3l-l=8
2l=8 |:2
l=4 cm
L=4+8
L=12 cm
P=2(L+l)
P=2·(12+4)
P=2·16
P=32 cm

3.
24+(24+5)+(24+10)+(24+15)+(24+20)=
24+29+34+39+44=
53+73+44=
126+44=170
250-170=80 pagini mai are de citit

1.
Predecesorul lui 100 este 99
99·3=297
297+99=296

2.
2, 4, 6, 8, 10
2+4+6=12
6+8+10=24
24-12=12

3.
a+b+c=91
b=a+1
c=30
a+a+1+30=91
2a+31=91 |-31
2a=91-31
2a=60 |:2
a=30
b=30+1
b=31