Question

1) rezultatul calculului 5-5:(1 supra4+1supra2+1supra2)este......?
2)suma primelor 10 zecimale ale numarului 2 supa15 este .....?
3)calculati {2,05+[2,75-(0,31+0,44)+2]}*2la a2+2intregi3supra4=
4) aflatix
a)(2,03+x):10la a 2=3,5
b)(x+1)*4,5-6,9=11,1
c)4,5:x<1,5in multimeaN
5)cu 0,(3)din banii economisiti ioana isi cumparacarti,apoi cu un sfert din bani ramasi cumpara o geanta,iar cu 50 lei ii cumpara un cadou mamei.stiind ca i-au ramas 70 lei ,aflati ce suma a avut la inceput si cat a cheltuit de fiecare data
6) un zid de caramida are dimensiunile L=Em ,l=0,3 si h=2,7m cate caramizi sunt necesare, daca o caramida are dimensiunile 30 cm ,15cm si 20 cm
dau coronita urgent

Answer 1

1) rezultatul calculului 5-5:(1/4+1/2+1/2)=5-5:(1+2+2)/4 =5-5x4/5=5-4=1

2)suma primelor 10 zecimale ale numarului 2 supa15 este 28
2:15=0,1(3)
deci suma primelor 10 zecimale 1+9x3=28

3)calculati {2,05+[2,75-(0,31+0,44)+2]}*2²+2intregi3/4=
={2,05+[2,75-0,75+2]}*2²+11/4=
=[2,05+(2+2)]*4+11/4=
=(2,05+4)*4+11/4=
=6,05*4+11/4=
=24,2+11/4=
=(96,8+11)/4=
=107,8/4=26,95

4) aflatix
a)(2,03+x):10²=3,5
2,03+x=350
x=350-2.03
x=347,97

b)(x+1)*4,5-6,9=11,1
4,5x+4,5-6,9=11,1
4,5x=13,5
x=3

c)4,5:x<1,5in multimeaN
4,5<1,5x
x>4,5:1,5
x>3  x∈(4,5,...∞)

5)cu 0,(3)din banii economisiti ioana isi cumpara carti,apoi cu un sfert din bani ramasi cumpara o geanta,iar cu 50 lei ii cumpara un cadou mamei.stiind ca i-au ramas 70 lei ,aflati ce suma a avut la inceput si cat a cheltuit de fiecare data
0,(3)=3/9=1/3
x=suma initiala
x/3=carti
x-x/3=2x/3 =rest
2x/3:4=2x/12=geanta
50 =cadou mama
70 lei rest
x/3+2x/12+50+70=x
4x+2x+1440=12x
6x=1440
x=240 lei
240:3=80 lei carti
240-80=160
160:4=40 lei geanta
160-40=120
50lei cadou mama
120-50=70 lei rest



6) un zid de caramida are dimensiunile L=3m ,l=0,3 si h=2,7m cate caramizi sunt necesare, daca o caramida are dimensiunile 30 cm ,15cm si 20 cm

V=3x0,3x2,7=2,43 m³
30 cm=0,3m
15cm=0,15 m
20cm=0,2 m
Vcaramida=0,3x0,15x0,2=0,009 m³
2,43 :0,009=270 caramizi

Answer 2

1) 5-5:(1/4+1/2+1/2)=5-5:(1/4+2/4+2/4)=
5-5:5/4=
5-5·4/5=5-4=1

2)
2/15=0,1(3)
suma primelor 10 zecimale 9x3+1=28

3){2,05+[2,75-(0,31+0,44)+2]}·2²+2intregi3/4=
{2,05+[2,75-0,75+2]}·4+11/4=
{2,05+4}·4+11/4=
6,05·4+11/4=
24,2+11/4=
242/10+11/4=(242·2+11·5)/20=(484+55)/20=539/20=26,95

4) 
a)(2,03+x):10²=3,5
2,03+x=3,5·100
2,03+x=350
x=350-2,03
x=347,97

b)(x+1)·4,5-6,9=11,1
(x+1)·4,5=11,1+6,9
(x+1)·4,5=18
x+1=18:4,5
x+1=4
x=4-1
x=3

c)4,5:x<1,5
45/10·1/x<15/10
45·10<15·10x
450<150x
-150x<-450    inmultim -1
x>450/150
x>3
x∈(3,+α)

5)0,(3)=3/9=1/3
x-bani economisiti
cartea:  x-x/3=(3x-x)/3=2x/3
geanta: 2x/3-1/4·(2x/3)=2x/3-x/6=(4x-x)/6=3x/6=x/2
x/2-50=70
x/2=70+50
x/2=120
x=120·2
x=240 lei a economisit

cat a costat cartea?
240·1/3=80 lei
cat a costat geanta?
(240-80):4=40 lei
cadoul a costat 50 lei
i-au mai ramas 70 lei

verificare
80+40+50+70=240