Question

Va rog frumos ajutati-ma la urmatoarea problema :
Aflati numerele a , b , c , d stiind ca a= (1/ 2+1,25) X 4
b = a- 3/4
c = 2,4 X(a-b) X 1 2 supra 3
d = 2 X b + 3/ a+c
Va rog frumos cu rezolvare (clasa a V-a)

Answer 1

1,25 este 125/100
125:100=1,25
100
=250
...200
...=500
.....500
.....=;=
$a = ( \frac{1}{2} + \frac{125}{100} ) \times 4$
Aducem la acelasi numitor comun si anume
$a = \frac{50 \times 1 + 125}{100} \times 4$
Impartim pe 100 la 4
100:4=25
.8
..20
...20
...==
$a = \frac{175}{25} \\ a = 7$
175:25=7
175
===

$b = 7 - \frac{3}{4}$
$b = \frac{7 \times 4 - 3}{4} \\ b = \frac{28 - 3}{4}$

$b = \frac{25}{4}$

C=24/10x(7-25/4)x(1x3+2)/3
C=24/10x(4x7-25)/4x5/3
C=24/10x(28-25)/4x5/3
C=24/10x3/4x5/3
24:4=6
3:3=1
10:5=2
Si ne rămâne
C=6/2x1/1x1/1
6:2=3
C=3

D=2x25/4+3/7+3
D=25/2+3/7+3
D=(7x25+2x3+14x3)/14
D=(175+6+42)/14
D=223/14

Answer 2

a = ( 1 / 2 + 125 / 100 ) × 4 = ( 1 /2 + 5 / 4 ) × 4 = ( 2 / 4 + 5 / 4 ) × 4 = 7 / 4 × 4 = 7 

a = 7 

b = a - 3 / 4 = 7 - 3 / 4 = 28 / 4 - 3 / 4 = 25 / 4 = 6,25 

c = 2,4  × ( 7 - 25 / 4 ) × 12 / 3 = 24 / 10 × ( 28 / 4 - 25 / 4 ) × 4  = 

= 12 / 5  ×  3 / 4  × 4 = 36 / 5 = 7,2 ( c) 

d = 2 × 25 / 4  +  3 / 7  + 72 / 10  =  25 / 2  + 3 / 7 + 36 / 5 = 

cmmmc al numitorilor ( 2, 7, 5 ) = 2 × 7 × 5 = 70

= ( 35 × 25 ) / 70  + ( 10 × 3) / 70 + ( 12  × 36 ) / 70 =

= 875 / 70 + 30 / 70 + 432 / 70 = 1 337 / 70 = 19,1 ( d)