Question

Aflati x-urile!
a)1,2x + 1 pe 3 - 1,(3)=0,5x
b)x+12 supra 15 - x+1 supra 5 = 0,(3)
c)5 supra 3-o,5*x=0,(12)+0,2(13)*x
d)7 supra 3 - $\frac{1-1 supra 2+0,5*x}{2,5-1,(3)}$ = 4 supra 3 * x-0,(36)
e)1 supra 3 { 1 supra 3[1 supra 3(1 supra 3 * x + 2]+2}-1=0

Answer 1

a)
12x/10 +1/3 -12/9= 5x/10
12x/10+1/3-4/3=5x/10
12x/10-5x/10 = 4/3-1/3
7x/10 = 3/3
7x/10=1
7x=10
x=10/7

b)  
(x+12)/15 - 3(x+1)/15 = 3/9
(x+12-3x-3)/15=1/3
(-2x+9)/15=5/15
-2x+9=5
-2x=5-9
-2x=-4
x=(-4):(-2)
x=2

c)
5/3 - 5x/10 = 12/99+211x/990
1650/990 -   495x/990 = 120/990 + 211x/990
1650-495x=120+211x
1650-120=211x+495x
1530 = 706 x
x=1530/706 = 765/353

d)
7/3 - [(0,5+0,5x)/ (25/10-12/9)]= 4x/3 -36/99
7/3 - [0,5(1+x)/ (5/2-4/3)]=4x/3 - 4/11
7/3 - [0,5(1+x)/(15-8/6)]=4x/3-4/11
7/3-[0.5(1+x)/(7/6)] = 4x/3-4/11
7/3 -[(1+x/2) * 6/7]=4x/3-4/11
7/3 - (3+3x)/7 = 4x/3 -4/11
7/3 - 3/7 - 3x/7 = 4x/3 -4/11
49/21 - 9/21 -9x/21 = 28x/21 -4/11
40/21+4/11 = 28x/21+9x/21
440/231 + 84/231 = 37x/21
524/231 = 37x/21
524/231=407x/231
524=407x
x=524/407