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Ajutor. Am lipsit de la ora si nu stiu sa rezolv. Ma puteti ajuta? Este urgent.

Ex. 15
Dau si coroana. va rog mult.


Ajutor Am Lipsit De La Ora Si Nu Stiu Sa Rezolv Ma Puteti Ajuta Este UrgentEx 15Dau Si Coroana Va Rog Mult class=

Răspuns :

a) 1 intreg 1/2=(1x2+1)/2=3/2
x/6=3/2·(2/3-x/2)   aducem paranteza la acelasi numitor
x/6=3/2·[(2·3-3x)/6]
x/6=3/2·(6-3x)/6    simplif.cu 3
x/6=1/2·(6-3x)/2
x/6=(6-3x)/4
4x=6(6-3x)
4x=36-18x
4x+18x=36
22x=36
x=36/22 simplif cu 2
x=18/11

b)
 1 intreg 3/5=(1·5+3)/5=8/5
x/5=8/5·(5/8-x/3)
x/5=8/5·[(5·3-8x)/24]    simplif cu 8
x/5=1/5·(15-8x)/3
x/5=(15-8x)/15
15x=5(15-8x)
15x=75-40x
15x+40x=75
55x=75
x=75/55 simplif cu 5
x=15/11

c)x/3=7/4·(4/7-x/2)
x/3=7/4·[(4·2-7x)/14]
x/3=1/4·(8-7x)/2
x/3=(8-7x)/8
8x=3(8-7x)
8x=24-21x
8x+21x=24
29x=24
x=24/29

d) (11x/6-7/4)·4/3=8x/9
[(11x·2-7·3)/12]·4/3=8x/9
[(22x-21)/12]·4/3=8x/9
simplif
[(22x-21)/3]·1/3=8x/9
(22x-21)/9=8x/9
22x-21=8x
22x-8x=21
14x=21
x=21/14 simplif
x=3/2

e) (10x/9-7/6)·2/5=x/5
[(10x·2-7·3)/18]·2/5=x/5    simplif
[(20x-21)/9]·1/5=x/5
(20x-21)/45=x/5
5(20x-21)=45x
100x-105=45x
100x-45x=105
55x=105     
x=105/55    simplif
x=21/11

f) (6x/5-7/8)·4/9=2x/9
[(6x·8-7·5)/40]·4/9=2x/9
[(48x-35)/10]·1/9=2x/9
(48x-35)/90=2x/9
9(48x-35)=2x·90       
432x-315=180x
432x-180x=315
252x=315
x=315/252
x=105/84
x=35/28