Răspuns:
279,2(7)
Explicație pas cu pas:
[tex]x = 12,(5) = \frac{125 - 12}{9} = \frac{113}{9}\\ y = 9,(6) = \frac{96 - 9}{9} = \frac{87}{9} [/tex]
[tex] \frac{x + y + z}{3} = \frac{201}{2} \\ x + y + z = \frac{3 \times 201}{2} \\z = \frac{603}{2} - (x + y)[/tex]
[tex]z = \frac{603}{2} - ( \frac{113}{9} + \frac{87}{9} ) = \frac{603}{2} - \frac{200}{9} = \frac{603 \times 9 - 200 \times 2}{2 \times 9} = \frac{5027}{18} = 279 \frac{5}{18} [/tex]
[tex] = > z = 279.2(7)[/tex]
