[tex]a + b + c = 630
\\ a - 12 = b - 16 = c - 17 = x\\ x + x +x = 630 -(12 + 16 + 17) = 630 - 45 \\ 3x = 585 \\ =\ \textgreater \ x = 585 : 3 = 195 \\ =\ \textgreater \ \\ a = x + 12 = 195 + 12 = 207 \\ b = x + 16 = 195 + 16 = 211 \\ c = x +17 = 195 +17 = 212[/tex]