Răspuns:
[tex] \frac{3}{10} \times x + 13 = \frac{3x + 130}{10} [/tex]
[tex]x - \frac{3x + 130}{10} = \frac{10x - 3x - 130}{10} = \frac{7x - 130}{10} [/tex]
[tex] \frac{2}{5 } \times \frac{7x - 130}{10} = \frac{7x - 130}{25} [/tex]
(3x+130)/10 +(7x-130)/25=(15x+650+14x-260)/50=(29x+390)/50
x-(29x+390)/50=93
50x-29x-390=4650
21x-390=4650
21x=4650+390
21x=5040
x=240