Question

Cine rezolvă acest exercițiu, primește 35 de puncte.


a) $( - \frac{9}{25} + \frac{1}{5} )$ · x = 0,(3) - 0,2
b) $( \frac{2}{5} - \frac{2}{5}x ) : \frac{2}{5} = 0,16$
c) $1 \frac{4}{5}$ · $( 1 \frac{1}{3} : 2 \frac{1}{3} - x$ · $1 \frac{1}{9} ) = \frac{1}{3}$ · $( \frac{1}{4} + \frac{1}{5} )$
d) $\frac{1}{4}$ · $( \frac{2x}{3} - 2) + \frac{x}{6} = \frac{3x - 1}{4}$
e) $\frac{x+4}{5} - \frac{x+2}{3} = \frac{2x}{15} - \frac{x+1}{3}$
f) $\frac{3x + 11}{6} + \frac{x-7}{2} = \frac{x-7}{2} = \frac{5x -1}{12} - 2 \frac{1}{6}$
g) 3(x+5) - 6(x-2) = 4(x+2) - 5(x-4)
h) 2(2x+7) + 3(x-1) = 6(x+3) - 18

Answer 1

a)  · x = 0,(3) - 0,2
0,(3)=3/9=1/3
(-9+5)x/25=1/3-2/10
-4x/25=(10-6)/30
-4x/25=4/30
-4x·30=4·25     (-1)
x=-4·25/4·30
x=-25/30 simplif.cu 5
x=-5/6
b) 
2/5(1-x):2/5=16/100
(2/5)·(5/2)(1-x)=16/100
10/10·(1-x)=16/100   simplif
1-x=4/25
25(1-x)=4
25-25x=4
-25x=4-25
-25x=-21           (-1)
x=21/25
c)  ·  ·  · 
10/5·(4/3:7/3-10x/9)=1/3·[(5+4)/20]
10/5·(4/3·3/7-10x/9)=1/3·9/20
10/5·(4/7-10x/9)=9/60   simplif
40/35-100x/45=3/20
-100x/45=3/20-40/35   simplif
-20x/9=(21-160)/140
-20x/9=-139/140           (-1)
20x·140=139·9
x=1251/2800
x=
d)  · 
1/4[(2x-6)/3]+x/6=(3x-1)/4
(2x-6)/3+x/6=(3x-1)/4
8(2x-6)+4x=6(3x-1)
16x-48+4x=18x-6
20x-18x=48-6
2x=42
x=42/2
x=21
(e) 
3(x+4)-5(x+2)=2x-5(x+1)
3x+12-5x-10=2x-5x-5
-2x+3x=-5-2
x=-7
f) 
ceva e gresit
g) 3(x+5) - 6(x-2) = 4(x+2) - 5(x-4)
3x+15-6x+12=4x+8-5x+20
-3x+27=-x+28
-3x+x=28-27
-2x=1      (-1)
x=-1/2
h) 2(2x+7) + 3(x-1) = 6(x+3) - 18
4x+14+3x-3=6x+18-18
7x+11=6x
7x-6x=-11
x=-11