3. Efectuați calculele și prezentați rezultatul sub forma unei fracții ireductibile.
Va rog dau coroana

Răspuns:
Explicație pas cu pas:
g)
x/(2x+1) + 1/(2x+1) + (3x+1)/(2x+1) = 2
= (x + 1 + 3 x + 1 ) / ( 2 x + 1 ) =
= ( 4 x + 2 ) / ( 2 x + 1 ) =
= 2(2 x + 1 ) / ( 2 x + 1 ) = => simplific cu ( 2 x + 1)
= 2
____________________________
h)
( 3 a + 2 b ) / ( a + b ) + ( 2 a + 3 b ) / ( a + b ) = 5
= ( 3 a + 2 b + 2 a + 3 b ) / ( a + b ) =
= ( 5 a + 5 b ) / ( a + b ) =
= 5(a+b) / (a+b) =
= 5
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i)
___ ___ __
abc/999 + cab/999 + bca/999 =(a+b+c)/9
= (100a+10b+c+100c+10a+b+100b+10c+a)/999 =
= (111a+111b+111c)/999 =
= 111(a+b+c)/999 = => simplific cu 111
= (a+b+c)/9
_____________________________________
j)
(5a+3)/(3a+6) - 3 a/(3a+6) + 1/(3a+6) = 2/3
= ( 5 a + 3 - 3 a + 1 ) /(3a+6) =
=(2a+4)/(3a+6) =
= 2(a+2)/3(a+2)=
= 2/3
______________________________
k)
2014/2014 - 2013/2014 + 2012/2014 - 2011/2014+ ...... + 2/2014 - 1/2014 =1/2
= ( 2014-2013+2012-2011+.....+2-1)/2014 =
= [( 2014-2013) + (2012-2011) + ( 2010-2009) +....+ ( 2-1) ]/2014=
=> 2014 : 2 = 1007 diferente sau: ( 2013 - 1) : 2 + 1 = 1007 nr. impare
= (1+1+1+.....+1)/2014 =
= 1 × 1007/2014 =
= 1/2
Explicație pas cu pas:
g.
[tex] \frac{x + 1 + 3x + 1}{2x + 1} = \frac{4x + 2}{2x + 1} = \\ \frac{2(2x + 1)}{2 x + 1} = \frac{2}{1} = 2[/tex]
h.
[tex] \frac{3x + 2y + 2x + 3y}{x + y} = \frac{5x + 5y}{x + y} = \\ \frac{5(x + y)}{x + y} = \frac{5}{1} = 5[/tex]
i.
[tex] \frac{111a + 111b + 111c}{999} = \frac{111(a + b + c)}{999} = \frac{a + b + c}{9} [/tex]
j. ???
K.
[tex] \frac{2014}{2014} - \frac{2013}{2014} + \frac{2012}{2014} - \frac{2011}{2014} + ... \\ + \frac{2}{2014} - \frac{1}{2014} = \frac{1 \times (2014 \div 2)}{2014} \\ = \frac{1007}{2014} = \frac{1}{2} [/tex]