Rezolvati ecuatia :
[tex] \frac{x + 1}{2} + \frac{x + 1}{4} + \frac{x + 1}{5} = 1[/tex]
în Q


Răspuns :


[tex] \frac{x + 1}{2} + \frac{x + 1}{4} + \frac{x + 1}{5} = \frac{10x + 10}{20} + \frac{5x + 5}{20} + \frac{4x + 4}{20} [/tex]
[tex] \frac{19x + 19}{20} = 1 < = > 19x + 19 = 20 < = > 19x = 20 - 19 = > x = \frac{1}{19} [/tex]
=> S=
[tex] \frac{1}{19} [/tex]

( x + 1) / 2 + ( x + 1) / 4 + ( x + 1) / 5 = 1


( x + 1) ( 1 / 2 + 1 / 4 + 1 / 5 ) = 1

→ il dau factor comun pe (x + 1 )

( x + 1 ) ( 10 / 20 + 5 / 20 + 4 / 20 ) = 1

( x + 1) × 19 / 20 = 1

( x + 1 ) × 19 = 20

19 x + 19 = 20

19 x = 20 - 19

x = 1 / 19